Improving In Vitro Generated Cartilage-Carrier-Constructs by Optimizing Growth Factor Combination

The presented study is focused on the generation of osteochondral implants for cartilage repair, which consist of bone substitutes covered with in vitro engineered cartilage. Re-differentiation of expanded porcine cells was performed in alginate gel followed by cartilage formation in high-density cell cultures. In this work, different combinations of growth factors for the stimulation of re-differentiation and cartilage formation have been tested to improve the quality of osteochondral implants. It has been demonstrated that supplementation of the medium with growth factors has significant effects on the properties of the matrix. The addition of the growth factors IGF-I (100 ng/mL) and TGF-beta1 (10 ng/mL) during the alginate culture and the absence of any growth factors during the high-density cell culture led to significantly higher GAG to DNA ratios and Young's Moduli of the constructs compared to other combinations. The histological sections showed homogenous tissue and intensive staining for collagen type II.