A novel injectable tissue-engineered bone composed of hADSCs and PRP

Objectives: To evaluate the osteogenic effects of human platelet-rich plasma (PRP) on human adipose tissue-derived stromal cells (hADSCs) in vitro and in vivo, and try to construct a novel, easily-obtained, and simply-performed injectable tissue-engineered bone composed of these two parts. Methods: PRP was obtained by traditional two-step centrifugation. Primary cultures of hADSCs were isolated from liposuction tissues of healthy patients. Two main growth factors, PDGF-AB and TGF-beta1, in the activated PRP were evaluated using ELISA assay. Activated PRP was added to cultural media of hADSCs with different concentrations to assess the effects of PRP on cell proliferation and osteogenic differentiation in vitro through MTT assays, quantitative alkaline phosphatase detection and quantitative calcium deposition assays. hADSCs cultured by activated PRP of optimal concentration were subcutaneously injected into the inguinal groove of nude mice with PRP and thrombin (injectable tissue-engineered bone). X-ray and H&E sections were used to observe the in vivo osteogenic capability of this construct after 4 weeks. Results: PRP contained high levels of TGF-beta1 and PDGF-AB. Cell attachment, proliferation and ALP activity and mineralization were enhanced by addition of PRP to the culture media, while the stimulatory effects of PRP presented in a dose-dependant manner. PRP in the concentration of 10% - 12.5% had the optimal proliferative and osteogenic effects. H&E section and X-ray detection confirmed that Injectable tissue-engineered bone composed of hADSCs and PRP could form bone structures in the inguinal groove of nude mice after 4 weeks. Conclusions: PRP in optimal concentration can enhance the cell adhesion, proliferation and induce the osteogenic differentiation of hADSCs in vitro and in vivo. Injectable tissue-engineered bone composed of hADSCs and PRP is a promising method for the reconstruction of bone defects due to their rich sources, lower donor site morbidity and convenient operation.