Macromer density influences mesenchymal stem cell chondrogenesis and maturation in photocrosslinked hyaluronic acid hydrogels

• Published in: Osteoarthritis and cartilage Vol. 17; no. 12; pp. 1639 - 1648
• Main Authors: Erickson, I.E, Huang, A.H, Sengupta, S, Kestle, S, Burdick, J.A, Mauck, R.L
• Format: Journal Article
• Language: English
• Published: England Elsevier Ltd 01.12.2009
• Subjects: Animals; Biomechanical Phenomena; Cartilage, Articular - metabolism; Cattle; Cells, Cultured; Chondrogenesis; Chondrogenesis - physiology; Extracellular Matrix - metabolism; Hyaluronic Acid - metabolism; Hydrogels - metabolism; Mechanical properties; Mesenchymal stem cells; Mesenchymal Stromal Cells - cytology; Mesenchymal Stromal Cells - metabolism; Photocrosslinked hydrogels; Rheumatology; Tissue Engineering - methods; Mechanical properties; Photocrosslinked hydrogels; Chondrogenesis; Mesenchymal stem cells
• ISSN: 1063-4584; 1522-9653
• DOI: 10.1016/j.joca.2009.07.003

Summary Objective Engineering cartilage requires that a clinically relevant cell type be situated within a 3D environment that supports cell viability, the production and retention of cartilage-specific extracellular matrix (ECM), and eventually, the establishment of mechanical properties that approach that of the native tissue. In this study, we investigated the ability of bone marrow derived mesenchymal stem cells (MSCs) to undergo chondrogenesis in crosslinked methacrylated hyaluronic acid hydrogels (MeHA) of different macromer concentrations (1, 2, and 5%). Design Over a 6 week culture period under pro-chondrogenic conditions, we evaluated cartilage-specific gene expression, ECM deposition within constructs and released to the culture media, and mechanical properties in both compression and tension. Further, we examined early matrix assembly and long term histological features of the forming tissues, as well as the ability of macromolecules to diffuse within hydrogels as a function of MeHA macromer concentration. Results Findings from this study show that variations in macromer density influence MSC chondrogenesis in distinct ways. Increasing HA macromer density promoted chondrogenesis and matrix formation and retention, but yielded functionally inferior constructs due to limited matrix distribution throughout the construct expanse. In 1% MeHA constructs, the equilibrium compressive modulus reached 0.12 MPa and s-GAG content reached nearly 3% of the wet weight, values that matched or exceeded those of control agarose constructs and that are 25 and 50% of native tissue levels, respectively. Conclusions These data provide new insight into how early matrix deposition regulates long term construct development, and defines new parameters for optimizing the formation of functional MSC-based engineered articular cartilage using HA hydrogels.