Cell-derived extracellular matrix scaffolds augmented with bone marrow aspirate concentrate promote cartilage regeneration

This study aimed to evaluate the effects of cell-derived (BMSCs and chondrocytes) extracellular matrix (ECM) scaffolds incorporating bone marrow aspirate concentrate (BMAC) on cartilage regeneration, and to determine whether BMAC-loaded BMSCs-derived (BM-d) ECM scaffolds were comparable to chondrocytes-derived (Ch-d) ECM scaffolds in terms of cartilage regeneration. In this study, BMSCs and chondrocytes were harvested and isolated, then developed into BM-d and Ch-d ECM scaffolds. The scaffolds were fully immersed in BMAC and subsequently utilized for inducing chondrogenic differentiation in vitro and cartilage regeneration in vivo. The in vitro results demonstrated that chondrogenesis was effectively promoted, accompanied by scaffold biodegradation, in both BM-d and Ch-d ECM groups as culture progressed over time. The ex vivo results, obtained using nude mice, showed that cartilage-like appearance gradually developed and cartilage matrix accumulation gradually increased in both groups over time. However, more significant calcium deposition was observed in the BM-d ECM group as time progressed. After 12 weeks of in vivo cartilage repair, white and smooth cartilage-like tissues had formed in the defect areas of both ECM groups. The regenerated tissues in both ECM groups fully integrated with the surrounding host tissues and exhibited higher mechanical properties compared to those in the microfracture group. Moreover, the in vivo histological and biochemical results indicated that more hyaline-like cartilage regenerated in both ECM groups, whereas more fibrocartilage formed in the microfracture group. In summary, our results suggest that BM-d and Ch-d ECM scaffolds loaded with BMAC can effectively promote cartilage regeneration both in vitro and in vivo, with BM-d ECM scaffolds being comparable to Ch-d ECM scaffolds.