(625d) Collagen Type I and II Blend Hydrogels with Mesenchymal Stem Cells As Scaffolds for Articular Cartilage Defect Repair

Since it is a major component of articular cartilage and plays a key role in chondrocyte function, collagen type II is a promising scaffold candidate to repair cartilage defects. However, compared to collagen type I, collagen type II exhibits poor mechanical properties when forming a physically crosslinked hydrogel. Thus, our lab previously developed and characterized hydrogel scaffolds made of a 3:1 collagen type I to collagen type II ratio (referred to as Col I/II gels) to harness the biological activity of collagen type II and the superior gelation of collagen type I [1].

In the current study, we investigated the chondrogenic differentiation potential of bone marrow-derived mesenchymal stem cells (MSCs) embedded within a Col I/II gel or an all collagen type I hydrogel (Col I) in vitro and the ability of MSCs encapsulated in a Col I/II gel to repair cartilage defects in vivo. The in vitro studies demonstrated that glycosaminoglycan (GAG) production in Col I/II hydrogels was statistically higher than in Col I hydrogels or pellet culture, and these results suggested that adding collagen type II promoted production of GAGs, a key component in cartilage extracellular matrix. Col I/II hydrogels had statistically lower alkaline phosphatase (AP) activity, an early bone indicator, than pellets cultured in chondrogenic medium (CM). The in vivo results demonstrated that the cellular morphology and proteoglycan staining for the Col I/II hydrogels matched that of articular cartilage tissue surrounding the repair tissue. We saw a greater degree of cartilage repair for the Col I/II hydrogels compared to the Col I hydrogels and the empty defect controls in both the medial condyle and the trochlear groove. Results from this study suggest that there is a clinical value in the cartilage repair capabilities of our Col I/II hydrogel with encapsulated MSCs.

References: [1] Vazquez-Portalatin N. et al., Biomacromolecules, 2016; 17: 3145-3152.