查看文章

Failures in fracture healing are mainly caused by a lack of vascularization. Adult human circulating CD34⁺ cells, an endothelial/hematopoietic progenitor-enriched cell population, have been reported to differentiate into osteoblasts in vitro; however, the therapeutic potential of CD34⁺ cells for fracture healing is still unclear. Therefore, we performed a series of experiments to test our hypothesis that functional fracture healing is supported by vasculogenesis and osteogenesis via regenerative plasticity of CD34⁺ cells. Peripheral blood CD34⁺ cells, isolated from total mononuclear cells of adult human volunteers, showed gene expression of osteocalcin in 4 of 20 freshly isolated cells by single cell reverse transcriptase-polymerase chain reaction analysis. Phosphate-buffered saline, mononuclear cells, or CD34⁺ cells were intravenously transplanted after producing nonhealing femoral fractures in nude rats. Reverse …