title: Effects of PB-EPCs on Homing Ability of Rabbit BMSCs via Endogenous SDF-1 and MCP-1.
abstract: Traumas, infections, tumors, and some congenital malformations can lead to bone defects or even bone loss. The goal of the present study was to investigate whether inclusion of endothelial progenitor cells derived from peripheral blood (PB-EPCs) in cell-seeded partially deproteinized bone (PDPB) implants would stimulate recruitment of systemically injected bone marrow stromal cells (BMSCs) to the implant.
  
  
  METHODS
  BMSCs were injected intravenously with lentiviral expression vector expressing enhanced green fluorescent protein (eGFP) for tracing. Recruitment of eGFP-positive BMSCs was tested for the following implant configurations: 1) seeded with both BMSC and PB-EPC, 2) BMSC alone, 3) PB-EPC alone, and 4) unseeded PDPB. Protein and mRNA levels of endogenous stromal-derived factor-1 (SDF-1) and its receptor CXCR4, as well as monocyte chemotactic protein-1 (MCP-1) and its receptor CCR2, were evaluated on the 8th week. Immunohistochemical staining was performed to determine eGFP-positive areas at the defective sites. Masson's trichrome staining was conducted to observe the distribution of collagen deposition and evaluate the extent of osteogenesis.
  
  
  RESULTS
  The mRNA and protein levels of SDF-1 and CXCR4 in the co-culture group were higher than those in other groups (p < 0.05) 8 weeks after the surgery. MCP-1 mRNA level in the co-culture group was also higher than that in the other groups (p < 0.05). Immunohistochemical assays revealed that the area covered by eGFP-positive cells was larger in the co-culture group than in the other groups (p < 0.05) after 4 weeks. Masson's trichrome staining revealed better osteogenic potential of the co-culture group compared to the other groups (p < 0.05).
  
  
  CONCLUSIONS
  These experiments demonstrate an association between PB-EPC and BMSC recruitment mediated by the SDF-1/CXCR4 axis that can enhance repair of bone defects.
authors.affiliation: Department of Plastic Surgery, the First Affiliated Hospital of Kunming Medical University, Kunming, Yunnan Province, PR of China.
authors.forename: Hanxiao
authors.initials: H
authors.lastname: Wei
authors.affiliation: Department of Plastic Surgery, the First Affiliated Hospital of Kunming Medical University, Kunming, Yunnan Province, PR of China.
authors.forename: Xian
authors.initials: X
authors.lastname: Zhao
authors.affiliation: Department of Plastic Surgery, the First Affiliated Hospital of Kunming Medical University, Kunming, Yunnan Province, PR of China.
authors.forename: Ruihong
authors.initials: R
authors.lastname: Yuan
authors.affiliation: Department of Plastic Surgery, the First Affiliated Hospital of Kunming Medical University, Kunming, Yunnan Province, PR of China.
authors.forename: Xiaoming
authors.initials: X
authors.lastname: Dai
authors.affiliation: Department of Plastic Surgery, the First Affiliated Hospital of Kunming Medical University, Kunming, Yunnan Province, PR of China.
authors.forename: Yisong
authors.initials: Y
authors.lastname: Li
authors.affiliation: Department of Plastic Surgery, the First Affiliated Hospital of Kunming Medical University, Kunming, Yunnan Province, PR of China.
authors.forename: Liu
authors.initials: L
authors.lastname: Liu
mesh_terms: D000818:Animals; D001854:Bone Marrow Cells / Q000166:cytology*; D002478:Cells, Cultured; D018932:Chemokine CCL2 / Q000032:analysis / Q000235:genetics / Q000378:metabolism*; D054377:Chemokine CXCL12 / Q000032:analysis / Q000235:genetics / Q000378:metabolism; D018920:Coculture Techniques; D003094:Collagen / Q000378:metabolism; D066026:Endothelial Progenitor Cells / Q000166:cytology* / Q000378:metabolism / Q000637:transplantation; D004797:Enzyme-Linked Immunosorbent Assay; D049452:Green Fluorescent Proteins / Q000378:metabolism; D007150:Immunohistochemistry; D045164:Mesenchymal Stem Cell Transplantation; D059630:Mesenchymal Stem Cells / Q000166:cytology / Q000378:metabolism*; D012333:RNA, Messenger / Q000378:metabolism; D011817:Rabbits; D060888:Real-Time Polymerase Chain Reaction; D054390:Receptors, CCR2 / Q000235:genetics / Q000378:metabolism; D054398:Receptors, CCR4 / Q000235:genetics / Q000378:metabolism
chemical_list: D018932:Chemokine CCL2; D054377:Chemokine CXCL12; D012333:RNA, Messenger; D054390:Receptors, CCR2; D054398:Receptors, CCR4; C485184:enhanced green fluorescent protein; D049452:Green Fluorescent Proteins; D003094:Collagen