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BACKGROUND:Bone defects are caused by many factors,such as inflammation,tumor,trauma or bone diseases.Erythropoietin can promote the differentiation of mesenchymal stem cells into osteoblasts and osteoclasts and act on vascular endothelial cells to induce angiogenesis and accelerate the repair of bone and cartilage defects.Erythropoietin is a growth factor with potential application in bone tissue engineering construction. OBJECTIVE:To expound the application and potential mechanism of erythropoietin in bone tissue engineering. METHODS:The first author searched the related articles published in CNKI,WanFang,VIP,and PubMed databases from 2004 to 2022 by computer.Search terms were"erythropoietin,bone defect,bone regeneration,angiogenesis,osteogenesis,osteoblast,osteoclast,bone tissue engineering"in Chinese and English.Finally,64 articles were included for review. RESULTS AND CONCLUSION:(1)Erythropoietin can directly act on osteoblasts and osteoclasts in the bone marrow microenvironment by promoting the differentiation of mesenchymal stem cells into osteoblasts,osteoclasts,adipocytes,nerve cells and stromal cells.The activation of Wnt/β-catenin,hypoxia-inducible factor 1α/vascular endothelial growth factor,p38 MAPK and EphrinB2/EphB4 signaling pathways mediates the osteogenic differentiation of mesenchymal stem cells.(2)Erythropoietin can not only regulate the production of erythrocytes to alter the oxygen-carrying capacity of blood but also stimulate vascular endothelial cells to promote angiogenesis.The new blood vessels can carry oxygen,nutrients,growth factors,and bone progenitor cells necessary for osteogenesis to the osteogenic site,thereby promoting bone formation and fracture healing.(3)Currently,erythropoietin is being used as a growth factor with osteogenic and angiogenic effects in various types of scaffold materials such as chitosan,polycaprolactone,bioceramics,and nanofibers through various drug delivery methods.Erythropoietin,along with other growth factors such as bone morphogenetic protein-2 and bone morphogenetic protein-9,has been applied to the surface of scaffold materials to participate in the repair of bone defects.Erythropoietin has demonstrated excellent practicality in the construction of new tissue-engineered bone and has potential clinical application value.
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Objective To prospectively compare cadmium-zinc-telluride (CZT) SPECT gated myocardial perfusion imaging (GMPI),conventional SPECT MPI and cardiac MRI for the assessment of left ventricular volume and ejection fraction in patients with heart failure.Methods From July 2016 to October 2016,a total of 35 patients (27 males,8 females,average age:(52.7±14.9) years) with heart failure were consecutively included.All patients underwent CZT SPECT GMPI,conventional SPECT GMPI and cardiac MRI within 7 d.LVEDV,LVESV and LVEF of three imaging modalities were calculated.One-way analysis of variance,Pearson correlation analysis and Bland-Altman analysis were used.Results CZT SPECT showed excellent correlation with conventional SPECT for LVEDV,LVESV and LVEF (r values:0.983,0.986 and 0.910,respectively;all P＜0.001).Bland-Altman analysis revealed good agreement between CZT SPECT and conventional SPECT for LVEDV,LVESV and LVEF.The correlation between CZT SPECT and cardiac MRI for LVEDV,LVESV and LVEF were all significant (r values:0.864,0.896 and 0.836,respectively;all P＜0.001).Compared with cardiac MRI,CZT SPECT showed systemic underestimation of LVEDV and LVESV and good agreement of LVEF by Bland-Altman analysis.Conclusions CZT SPECT has high clinical value for patients with heart failure.Despite underestimating LVEDV and LVESV,it correlated well with cardiac MRI.It also has a good agreement with conventional SPECT on left ventricular volume and LVEF.