3-D Osteochondral Micro-tissue to Model Pathogenesis of Osteoarthritis

描述(申请人提供)：骨关节炎(OA)是最常见的关节炎形式，影响多达15%的成年人，主要特征是关节的关节软骨成分退化，通常伴有软骨下骨损伤。了解骨性关节炎发病机制对于合理开发治疗骨性关节炎的药物(DMOAD)具有重要意义。虽然大多数关于骨性关节炎的研究都集中在关节软骨或骨成分的研究上，但骨软骨复合体是一个更具生理学意义的靶点，因为该病最终是一种骨软骨完整性和功能的紊乱。在这一应用中，我们建议构建一个体外三维微系统，以模拟关节骨软骨复合体的结构和生物学。成人骨髓间充质干细胞(MSCs)将用于生产成骨和软骨组织成分，这些细胞来源于骨髓和脂肪，种植在具有特定内部结构的生物材料支架中。设计了一种3D打印的可供灌流的容器平台，其尺寸适合96孔培养板格式，以容纳和维护骨软骨微系统，该微系统具有以下特征：(1)具有功能界面的解剖软骨/骨两相结构；(2)来自单个成人间充质干细胞来源的所有组织成分，以消除可能的年龄/组织类型不相容；(3)单独的隔室，以构成用于“滑膜”和“骨”成分的分离微环境；(4)细胞种植的信封，代表“滑膜”和“内皮”；(5)可通过引入生物活性物质或候选效应细胞以及组织/介质采样和成分分析来控制和调节的可接近的单个隔室；(6)与机械载荷和扰动的应用的兼容性；以及(7)允许进行非侵入性功能监测的成像能力。将在以下基础上测试骨软骨微系统的健壮性和生理学相关性：(1)分离的“滑膜”和“骨”间隔的结构完整性和潜在连通性；(2)保持不同的软骨和骨骼表型，以及形成组织学上不同的骨软骨连接或潮标；(3)适用性和组织对机械负荷的反应；以及(4)成像和分析能力。将在骨软骨微系统中检查机械损伤、暴露于炎性细胞因子和骨质量受损对软骨成分退行性变化的影响，作为最终应用于改进的高通量体外模型的第一步，用于预测候选DMOADs的有效性、安全性、生物利用度和毒理学结果。

DESCRIPTION (provided by applicant): Osteoarthritis (OA), the most prevalent form of arthritis, affects up to 15% of the adult population and is principally characterized by degeneration of the articular cartilage component of the joint, often with accompanying subchondral bone lesions. Understanding the mechanisms underlying the pathogenesis of OA is important for the rational development of disease modifying OA drugs (DMOADs). While most studies on OA have focused on the investigation of either the cartilage or the bone components of the articular joint, the osteochondral complex represents a more physiologically relevant target as the disease ultimately is a disorder of osteochondral integrity and function. In this application, we propose to construct an in vitro 3-dimensional microsystem that models the structure and biology of the osteochondral complex of the articular joint. Osteogenic and chondrogenic tissue components will be produced using adult human mesenchymal stem cells (MSCs) derived from bone marrow and adipose seeded within biomaterial scaffolds photostereolithographically fabricated with defined internal architecture. A 3D-printed, perfusion-ready container platform with dimensions to fit into a 96-well culture plate format is designed to house and maintain the osteochondral microsystem that has the following features: (1) an anatomic cartilage/bone biphasic structure with a functional interface; (2) all tissue components derived from a single adult mesenchymal stem cell source to eliminate possible age/tissue type incompatibility; (3) individual compartments to constitute separate microenvironment for the "synovial" and "osseous" components; (4) cell-seeded envelopes to represent "synovium" and "endothelium"; (5) accessible individual compartments that may be controlled and regulated via the introduction of bioactive agents or candidate effector cells, and tissue/medium sampling and compositional assays; (6) compatibility with the application of mechanical load and perturbation; and (7) imaging capability to allow for non-invasive functional monitoring. The robustness and physiological relevance of the osteochondral microsystem will be tested on the basis of: (1) structural integrity and potential connectivity of the separate "synovial" and "osseous" compartments; (2) maintenance of distinct cartilage and bone phenotypes and the development of a histologically distinct osteochondral junction or tidemark; (3) applicability and tissue responsiveness to mechanical loading; and (4) imaging and analytical capabilities. The consequences of mechanical injury, exposure to inflammatory cytokines, and compromised bone quality on degenerative changes in the cartilage component will be examined in the osteochondral microsystem as a first step towards its eventual application as an improved and high-throughput in vitro model for prediction of efficacy, safety, bioavailability, and toxicology outcomes for candidate DMOADs.