Fibronectin stimulates migration and proliferation, but not chondrogenic differentiation of human subchondral progenitor cells.

Aims: To evaluate the impact of human plasma-derived fibronectin (FN) on human subchondral mesenchymal progenitor cells regarding cell migration, proliferation, and chondrogenic differentiation. Materials & methods: Human subchondral mesenchymal progenitor cells were analyzed for their migration capacity upon treatment with human plasma-derived FN. Proliferation activity was evaluated by DNA content. For chondrogenesis, cells were cultured in high-density pellet cultures in the presence of FN, TGF-beta 3, and a combination thereof. Results: Treatment of progenitors with FN significantly increased the number of migrating cells and elevated proliferative activity. Histological staining indicated formation of an extracellular matrix with type II collagen. Gene expression analysis gave no evidence for chondrogenic differentiation mediated by FN, but revealed a significant induction of type II collagen expression. Conclusion: FN has a potential to recruit human subchondral mesenchymal progenitor cells, possibly supporting proliferation and matrix assembly in cartilage repair procedures using bioactive implants after microfracture treatment.