Positive role of calcium phosphate ceramics regulated inflammation in the osteogenic differentiation of mesenchymal stem cells

Recently, researches have confirmed the crucial role of inflammatory response in Ca-P ceramic-induced osteogenesis, however, the underlying mechanism has not yet been fully understood. In this study, BCP and beta-TCP ceramics were used as material models to investigate the effect of physicochemical properties on inflammatory response in vitro. The results showed that BCP and beta-TCP could support macrophages attachment, proliferation, and spreading favorably, as well as promote gene expressions of inflammatory related cytokines (IL-1, IL-6, MCP-1, and TNF-alpha) and growth factors (TGF-beta, FGF, PDGF, VEGF, IGF, and EGF). BCP showed a facilitating function on the gene expressions earlier than beta-TCP. Further coculture experiments performed in vitro demonstrated that the CMs containing various increased cytokines for macrophages pre-culture could significantly promote MSCs osteogenic differentiation, which was confirmed by the gene expressions of osteogenic specific markers and the intracellular OCN product accumulation under the stimulation of BCP and beta-TCP ceramics. Further evidence was found from the formation of mineralized nodules in BCM and TCM. In addition, this study showed a concise relationship between Ca-P ceramic induced inflammation and its osteoinductivity that the increased cytokines and growth factors from macrophages could promote MSCs osteogenic differentiation.