PHBV and predifferentiated human adipose-derived stem cells for cartilage tissue engineering

This study was conducted to investigate whether in vitro chondrogenic differentiated human adipose-derived stem cells (hASCs) can maintain the chondrogenic phenotype in (3-hydroxybutrate-co-3-hydroxyvalerate) (PHBV) scaffolds and whether differentiated hASCs/PHBV construct can produce neocartilage in a heterotopic animal model. hASCs were cultured with or without chondrogenic media in vitro and then seeded on PHBV foams. Differentiated cell/PHBV constructs were subcutaneously implanted in nude mice for 8 or 16 weeks; nondifferentiated cell/PHBV constructs were implanted in the control group. The results in the control group showed no cartilage formation and the disappearance of the scaffold at 8 weeks. Conversely, all differentiated hASCs/PHBV implants kept their original shape throughout 16 weeks. These implants at 16 weeks had stronger chondrocytes-specific histochemical staining than those at 8 weeks, with GAG, total collagen, and compressive moduli increased with implantation time. Cartilage lacunae were observed in all retrieved implants at 16 weeks. The chondrocytes-specific genes were detected by RT-PCR at 16 weeks. The remnants of PHBV were observed in the implants throughout 16 weeks. This study demonstrates that chondrogenic predifferentiated hASCs have the ability to maintain a chondrogenic phenotype in PHBV and that cell/PHBV constructs can produce neocartilage in a heterotopic site, but the degradation rates of PHBV in different environments needs more investigation.