Novel approach to engineer implantable nasal alar cartilage employing marrow precursor cell sheet and biodegradable scaffold.

Repair of nasal and auricular malformation remains an obstacle for clinicians because of poor regenerative capacity of cartilage and limitation of donor sites. In the current study, we developed a novel approach to regenerate implantable nasal alar cartilage by using marrow precursor cell (MPC) sheet and biodegradable scaffold of polylactic acid-polyglycolic acid copolymer (PLGA).Rabbit MPCs were expanded and induced by transforming growth factor-beta to improve chondrocyte phenotype. MPC sheets were obtained by continuous culture and used to wrap PLGA scaffold in the shape of the human nasal alar. The constructs were incubated in a spinner flask for 4 weeks, and cartilage formation was investigated by gross inspection and histological examination. The constructs were then implanted subcutaneously into a nude mouse. Specimens were harvested and analyzed 4 weeks after implantation.The results showed that cartilaginous tissue formed and PLGA absorbed during in vitro incubation. Histological analysis showed engineered cartilage consisted of evenly spaced lacunae embedded in a matrix rich in proteoglycans, and kept the initial shape of the nasal alar. Based on this "MPC sheet combining polymer strategy," implantable nasal alar could be successfully regenerated.This strategy has the advantage of high cell transplantation efficiency and great potential for clinical application.