Bio-engineering of fetal cartilage for in utero spina bifida repair.

During in utero surgical spina bifida repair, a multi-layer closure is used to cover the defect. These soft tissues, however, might be not sufficient to protect the spinal cord during the future life. Our goal is to develop a more rigid protective tissue construct consisting of bioengineered cartilage and skin. Ovine fetal chondrocytes were tested for their in vitro chondrogenic potential in three-dimensional cultures. Scaffolds based on natural biopolymers (collagen I, fibrin glue) were loaded with varying amounts of fetal chondrocytes and assessed for their ability to support cartilage formation in vitro. The bioengineered constructs were analyzed using cartilage-specific histology stainings and compared to native fetal cartilage. Fetal chondrocytes actively produced cartilage extracellular matrix in three-dimensional cultures, even at high passages. Among all bioengineered scaffolds, only the collagen I-based hydrogels loaded with high densities of fetal chondrocytes showed cartilage-like structure in vitro but also extensive shrinking. Fetal chondrocytes represent a good cell source for cartilage bioengineering. Collagen I scaffolds support cartilage formation in vitro, but the construct shrinking constitutes a major limitation. Future steps include the identification of suitable bioprintable materials which maintain their shape and size, as well as the analysis of the interphase between bioengineered cartilage and skin.