Current Challenges in Cartilage Tissue Engineering: A Review of Current Cellular-Based Therapies

Injectable and 3D Bioprinted Polysaccharide Hydrogels: From Cartilage to Osteochondral Tissue Engineering

“…The hyaline articular cartilage functions to provide gliding low-friction surface, shock absorption and protects the underlying supporting subchondral bone from pressure which in turn complement the mechanical strength. ,− The biomechanical role especially the compressive properties of cartilage is based on the interstitial fluid swelling pressure of proteoglycans, mostly associated in aggregates comprising complexes of aggrecans. Aggrecan aggregates are generated by the attachment of brush-like chondroitin sulfate or keratin sulfate with the protein core (aggrecan) with hyaluronic acid and a link protein for stabilization. ,− Additionally, hydrated collagen II stabilized by collagens IX and XI, noncollagenous proteins, and lesser amounts of small proteoglycans such as biglycan, fibromodulin, and decorin contributes to the organization and thereby regulates functions of the cartilage matrix. ,,, The additional functions of matrix include protection for chondrocytes, mediation of nutrient transfer, and serve as storage for cytokines and growth factors for chondrocyte homeostasis . Chondrocytes are highly specialized, sparsely distributed cells that synthesize and maintain their resident matrix by regulating matrix metabolism.…”

“…Articular cartilage, a low friction articulation diarthrodial joints at knees, hips, fingers, and lower spine region is an unusual biphasic tissue. Solid matrix of this tissue is composed of collagen II and proteoglycans as primary extracellular matrix (ECM) components and fluid phase is synovium. , Cartilage is avascular, aneural, and alymphatic in nature and unlike other tissues, homogeneous population of sparse chondrocytes (2–5%) residing in porous matrix contribute to the ECM maintenance, which in turn nourishes the chondrocytes. , The components of a few millimeters thick cartilage provides required mechanical properties, enabling biomechanical functions such as dissipation of compressive loads and shock absorption and allows frictionless pain-free movement. ,,, Complementary to the cartilage compressive strength, the underlying harder subchondral bone contributes due to its large area and provides anchorage for collagen fibrils of articular cartilage . However, in the case of arthritic joint evidenced by extensive cartilage tissue damage, an imbalance occurs between the matrix synthesis and degradation of the major matrix glycocomponents due to loss of chondrocytes and adverse inflammatory responses .…”

Advanced Strategies for Articular Cartilage Defect Repair

“…The scaffolds are required to provide the “template” for the cells to lay down synthesized matrix or potentially provide biological cues for modulating cell behavior such as proliferation, migration and differentiation. The biological signaling molecules are required to stimulate progenitor cell recruitment, differentiation as well as directing desired tissue synthesis [ 37 ]. This review will cover these governing areas of tissue engineering and highlight some of the recent advances in this rapidly growing field with specific application to cartilage defect repair.…”

Development of silk fibroin tissue engineering scaffolds via indirect additive manufacturing for cartilage regeneration

“…The other contributing components include distribution of cells in the defect and the use of cell carriers/scaffolds [73]. For scaffold-based ACI, chemical and physical properties such as cell-biomaterial interaction, pore size and porosity also influence the cell density used [5].…”

“…The auricular and nasal septum cartilages provide defined shapes for aesthetic purposes while the TMJ cartilages are known to have moderate weight-bearing capabilities for effective masticatory actions. In orthopaedics , articular cartilages provide low-friction gliding surfaces that are essential for smooth functional movements while distributing the bearing load evenly across the relevant joint [4,5].…”