Center for Cellular and Molecular Engineering, Department of Orthopaedic Surgery, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA; BIOlab Research Group, Department of Chemistry and Industrial Chemistry, University of Pisa, Pisa, Italy.
Center for Cellular and Molecular Engineering, Department of Orthopaedic Surgery, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA; Ri.MED Foundation, Palermo, Italy.
Biomaterials. 2021 May;272:120773. doi: 10.1016/j.biomaterials.2021.120773. Epub 2021 Mar 22.
The generation of engineered models of the osteochondral complex to study its pathologies and develop possible treatments is hindered by the distinctly different properties of articular cartilage and subchondral bone, with the latter characterized by vascularization. In vitro models of the osteochondral complex have been mainly engineered as biphasic constructs containing just cartilage and bone cells, a condition very dissimilar from the in vivo environment. The different cellular components of the osteochondral complex are governed by interacting biochemical signaling; hence, to study the crosstalk among chondrocytes, osteoblasts, and endothelial cells, we have developed a novel triphasic model of the osteochondral tissue interface. Wet-spun poly(ε-caprolactone) (PCL) and PCL/hydroxyapatite (HA) scaffolds in combination with a methacrylated gelatin (gelMA) hydrogel were used as the polymeric backbone of the constructs. The scaffold components were engineered with human bone marrow derived mesenchymal stem cells (hMSCs) and human umbilical vein endothelial cells (HUVECs), and differentiated using a dual chamber microphysiological system (MPS) bioreactor that allows the simultaneous, separate flow of media of different compositions for induced differentiation of each compartment towards a cartilaginous or osseous lineage. Within the engineered Microphysiological Vascularized Osteochondral System, hMSCs showed spatially distinct chondrogenic and osteogenic markers in terms of histology and gene expression. HUVECs formed a stable capillary-like network in the engineered bone compartment and enhanced both chondrogenic and osteogenic differentiation of hMSCs, resulting in the generation of an in vitro system that mimics a vascularized osteochondral interface tissue.
为了研究骨软骨复合体的病理学并开发可能的治疗方法，人们生成了工程化的骨软骨复合体模型，但关节软骨和软骨下骨具有明显不同的特性，后者具有血管化特征，这对模型的生成造成了阻碍。骨软骨复合体的体外模型主要是通过包含软骨细胞和骨细胞的双相构建来设计的，这种构建与体内环境非常不同。骨软骨复合体的不同细胞成分受到相互作用的生化信号的控制；因此，为了研究软骨细胞、成骨细胞和内皮细胞之间的串扰，我们开发了一种新型的骨软骨组织界面三相模型。湿纺聚己内酯（PCL）和 PCL/羟基磷灰石（HA）支架与甲基丙烯酰化明胶（gelMA）水凝胶结合，用作构建体的聚合物骨干。支架组件由人骨髓间充质干细胞（hMSCs）和人脐静脉内皮细胞（HUVECs）设计，并使用双室微生理系统（MPS）生物反应器进行分化，该生物反应器允许不同组成的培养基同时、分别流动，以诱导每个隔室向软骨或成骨谱系分化。在工程化的微生理血管化骨软骨系统中，hMSCs 在组织学和基因表达方面表现出空间上不同的软骨和成骨标志物。HUVECs 在工程化的骨腔中形成了稳定的毛细血管样网络，并增强了 hMSCs 的软骨和成骨分化，从而生成了一种模拟血管化骨软骨界面组织的体外系统。
