Innovative Tissue‐Engineered Strategies for Osteochondral Defect Repair and Regeneration: Current Progress and Challenges

Abstract

Clinical treatments for the repair of osteochondral defects (OCD) are merely palliative, not completely curative, and thus enormously unfulfilled challenges. With the in-depth studies of biology, medicine, materials, and engineering technology, the conception of OCD repair and regeneration should be renewed. During the past decades, many innovative tissue-engineered approaches for repairing and regenerating damaged osteochondral units have been widely explored. Various scaffold-free and scaffold-based strategies, such as monophasic, biphasic, and currently fabricated multiphasic and gradient architectures have been proposed and evaluated. Meanwhile, progenitor cells and tissue-specific cells have also been intensively investigated in vivo as well as ex vivo. Concerning bioactive factors and drugs, they have been combined with scaffolds and/or living cells, and even released in a spatiotemporally controlled manner. Although tremendous progress has been achieved, further research and development (R&D) is needed to convert preclinical outcomes into clinical applications. Here, the osteochondral unit structure, its defect classifications, and diagnosis are summarized. Commonly used clinical reparative techniques, tissue-engineered strategies, emerging 3D-bioprinting technologies, and the status of their clinical applications are discussed. Existing challenges to translation are also discussed and potential solutions for future R&D directions are proposed.

Nanoparticle–Cartilage Interaction: Pathology-Based Intra-articular Drug Delivery for Osteoarthritis Therapy

“…Advances in cell therapy have emphasized the role of chondrocytes and mesenchymal stem cells (MSCs) with chondrogenic differentiation ability, migratory, anti-inflammatory and/or immunosuppressive properties in treating cartilage lesions (Fig. 10b, e) [256]. A noninvasive means of imaging and tracking the cell fate after in vivo implantation could be extremely valuable.…”

Osteochondral Tissue Engineering: The Potential of Electrospinning and Additive Manufacturing

“…Such biomimicking constructs can then be implanted into a damaged OC region, where they will assist tissue repair, promote regenerative responses, and facilitate the functional recovery of the joint. Reprinted from [ 243 ] with permission from Wiley Online Library. Copyright © 2020, John Wiley & Sons, Inc.…”

Osteochondral tissue engineering: Perspectives for clinical application and preclinical development

“…Careful selection of appropriate biomaterial is an important aspect for tissue engineering research. Biomaterials, fabrication process, and growth factors for OC TE have been comprehensively summarized in the previous reviews on osteochondral tissue engineering [ 6 , 7 ]. Various biomaterials, natural or synthetic, have been tested and resulted in positive histological outcomes for OCD repair as summarized in supplementary tables, hence based on current published data it's difficult to give recommendations on biomaterials selection, and fabrication method.…”

“…In recent decades, the field of osteochondral tissue engineering has seen significant development in biomaterials and fabrication technologies, providing feasible approaches to develop implantable constructs that have the potential to achieve better clinical outcomes. Previous reviews have described the gradient physiological characteristics of osteochondral tissue and gradient scaffold design for OCDs [ 3 ], tissue engineering strategies, biomaterials and fabrication technologies [ [4] , [5] , [6] , [7] ]. However, the discussion on bridging the gap between the clinical need and preclinical research is still limited, on which we focus in the present review, providing an insight into what is currently lacking in TE methods that failed to yield satisfactory outcomes, and what is needed to further improve these techniques.…”