Repairing Cartilage with Processed Chondrocyte Constructs: A 6-Month Study Using a Porcine Model

Autologous chondrocyte implantation was the first cell-based therapy that used a tissue engineering process to repair cartilage defects. Recently improved approaches and tissue-engineered cell constructs have been developed for growing patient populations. We developed a chondrocyte construct using a collagen gel and sponge scaffold and physicochemical stimuli, implanted with a surgical adhesive. We conducted a proof-of-concept study of these improvements using a cartilage defect model in miniature swine.

We implanted the autologous chondrocyte constructs into full-thickness chondral defects in the femoral condyle, compared those results with empty and acellular scaffold controls, and compared implantation techniques with adhesive alone and with partial adhesive with suture. Two weeks after the creation of the defects and implantation of the cellular or acellular constructs, we arthroscopically confirmed that the implanted constructs remained at the chondral defects. We evaluated the regenerated tissue macro- and microscopically 6 months after the cell constructs were implanted. The tissues were stained with Safranin-O and evaluated using Sellers' histology grading system.

The defects implanted with processed cell constructs and acellular scaffolds were filled with chondrocyte-like round cells and with nearly normal tissue architecture that were significantly greater degree compared to empty defect control. Even with the adhesive alone and with suture alone, the cell construct was composed of the dense cartilaginous matrix that was found in the implantation using both the sutures and the adhesive.

Implantation of cell constructs promoted regeneration and integration of articular cartilage at chondral defects in swine by 6 months.