Hyaluronan-based biopolymers as delivery vehicles for bone-marrow-derived mesenchymal progenitors

The tolerability and safety of hyaluronan-based three-dimensional scaffolds as a culture vehicle for mesenchymal progenitor cells was investigated in this pilot study. The proliferation patterns and extracellular matrix produ ction of rabbit and human mesenchymal, bone-marrow-derived progenitors firs t were characterized in vitro. Subsequently rabbit autologous cells were cu ltured in this hyaluronan-based scaffold and implanted in a full-thickness osteochondral lesion. In vitro histologic findings showed that mesenchymal progenitor cells adhered and proliferated onto the hyaluronan-derived scaff old. Human stem cells were shown to produce the main extracellular matrix m olecules, accompanied by an occasional synthesis of mature type II collagen . bl vivo data demonstrated that the biomaterial, with or without mesenchym al progenitors, did not elicit any inflammatory response and was completely degraded within 4 months after implantation. With regard to the efficacy o f this cell therapy, even among the small number of animals tested there wa s histologic evidence that lesions filled with the biomaterial, either seed ed or unseeded with cells, achieved a faster and better healing compared to empty controls. The present data suggest that the hyaluronan-based scaffol ds are well tolerated and safe and may be a valuable delivery vehicle for t issue engineering in the repair of articular cartilage defects. (C) 2000 Jo hn Wiley & Sons, Inc.