The role of muscle-derived stem cells in bone tissue engineering.

The formation of bone and repair of bone defect requires a source of pluripotential mesenchymal stem cells. However, the capacity of the human body to generate bone components is limited. In this report, we show that the highly purified myogenic cells by the preplate technique have the capacity to differentiate into osteogenic lineage in vitro. The recombinant human bone morphogenic protein (rh-BMP-2) was immobilized on the molded gelatin composite. Primary muscle cells were isolated from newborn Wistar-rats calf muscle. The cells were then preplated in collagen-coated flasks. After six serial platings, the culture was enriched with small, round cells [pp6]. The effects of immobilized rhBMP-2 on the gelatin scaffold were evaluated by the analysis of alkaline phosphatase (ALP) and osteocalcin in culture medium after seedings of muscle-derived cells [pp6]. The results showed that the cells isolated from pp6 slow adhering cells possessed round mononuclear phenotype, marked ALP stain and matrix mineralization. The synthesis and secretion of ALP from pp6 muscle-derived cells were persistent higher than that of pp1-pp5 groups. The efficacy of rhBMP-2 immobilization on the gelatin scaffolds as manifested as the synthesis and secretion of ALP and osteocalcin from muscle-derived cells was always significantly higher than that of the control samples. In summary, our results suggest that the muscle-derived pp6 cells were capable of inducing and participating in bone formation. These results suggest that muscle tissue is a valuable resource for osteoprogenitor cells to be used in clinical practice to improve bone healing.