An in vitro chondro-osteo-vascular triphasic model of the osteochondral complex

Abstract

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(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 (microVOCS), 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.

Scaffold-Based Tissue Engineering Strategies for Osteochondral Repair

“…(H) Adapted with permission from ref ( Dehghani Nazhvani et al, 2021 ). Copyright 2021 by Elsevier Inc. (I) Adapted with permission from ref ( Pirosa et al, 2021 ). Copyright 2021 by Elsevier Ltd.…”

A Progress Report and Roadmap for Microphysiological Systems and Organ-On-A-Chip Technologies to Be More Predictive Models in Human (Knee) Osteoarthritis

“…Culturing cells in vitro also includes their cultivation in an artificial, stimulative, and supplemented fluid environment, mainly with the aim to promote proliferation. Especially stem cells are often differentiated into joint tissue-specific cells and progenitor cells ( Lin et al, 2014 ; O’Grady et al, 2019 ; Pirosa et al, 2021 ) for bone, cartilage, adipose, or connective tissue cells using differential cultivation protocols ( Lin et al, 2019 ). Given the cell population heterogeneity of resident mature and progenitor cell types in native OA tissues ( Stephenson et al, 2018 ; Cheng et al, 2021 ; Wang et al, 2021 ; Liu et al, 2022 ), stem cell approaches for future in vitro models must provide tissue-specific mature cell types with high phenotypic and genotypic authenticity in addition to a variety of heterogeneous progenitor cells.…”

“…Another aspect to consider is the need for multiphasic and heterogeneous differentiation protocols including divergent differentiation and cultivation durations for the proper maturation of cells within 3D models. A first step to address this challenge is to generate growth factor gradients to tune the differentiation of bioprinted multiphasic tissue constructs ( Lin et al, 2019 ; Pirosa et al, 2021 ). Nonetheless, with the increasing complexity of the microsystem, the spatial and temporal control of growth factor administration decreases.…”

Free or fixed state of nHAP differentially regulates hBMSC morphology and osteogenesis through the valve role of ITGA7

“…Currently, the incorporation of nHAP into 3D scaffolds are the most extensively applied form, which has so far demonstrated good therapeutic effects in bone tissue engineering [ [6] , [7] ]. However, these studies mainly focused on the repair effects of composite scaffolds, and the regulatory mechanisms of Cell-nHAP interaction are still poorly understood [ 8 ]. Some previous studies have tried to explore this mechanism using culture plate seeded with cells and culture medium added with nHAP, even though this is far from being the ideal way to explore in vivo mechanism.…”