title: A novel early precursor cell population from rat bone marrow promotes angiogenesis in vitro.
abstract: BACKGROUND
  Some studies demonstrated therapeutic angiogenesis attributable to the effects of endothelial progenitor cells (EPC), others have reported disappointing results. This may be due to the fact that EPC populations used in these contradictory studies were selected and defined by highly variable and differing experimental protocols. Indeed, the isolation and reliable characterization of ex vivo differentiated EPC raises considerable problems due to the fact there is no biomarker currently available to specifically identify EPC exclusively. On the other hand traditional differentiation of primary immature bone marrow cells towards the endothelial lineage is a time-consuming process of up to 5 weeks. To circumvent these shortcomings, we herein describe a facile method to isolate and enrich a primary cell population from rat bone marrow, combining differential attachment methodology with cell sorting technology.
  
  
  RESULTS
  The combination of these techniques enabled us to obtain a pure population of early endothelial precursor cells that show homogenous upregulation of CD31 and VEGF-R2 and that are positive for CD146. These cells exhibited typical sprouting on Matrigel™. Additionally, this population displayed endothelial tube formation when resuspended in Matrigel™ as well as in fibrin glue, demonstrating its functional angiogenic capacity. Moreover, these cells stained positive for DiI-ac-LDL and FITC-UEA, two markers that are commonly considered to stain differentiating EPCs. Based upon these observations in this study we describe a novel and time-saving method for obtaining a pure endothelial precursor cell population as early as 2-3 weeks post isolation that exhibits endothelial abilities in vitro and which still might have retained its early endothelial lineage properties.
  
  
  CONCLUSIONS
  The rapid isolation and the high angiogenic potential of these syngeneic cells might facilitate and accelerate the pre-vascularization of transplanted tissues and organs also in a human setting in the future.
authors.forename: Andreas
authors.initials: A
authors.lastname: Brandl
authors.forename: Quan
authors.initials: Q
authors.lastname: Yuan
authors.forename: Anja M
authors.initials: AM
authors.lastname: Boos
authors.forename: Justus P
authors.initials: JP
authors.lastname: Beier
authors.forename: Andreas
authors.initials: A
authors.lastname: Arkudas
authors.forename: Ulrich
authors.initials: U
authors.lastname: Kneser
authors.forename: Raymund E
authors.initials: RE
authors.lastname: Horch
authors.affiliation: Department of Plastic and Hand Surgery, Hospital of Erlangen, Friedrich-Alexander-University of Erlangen-Nuremberg, Krankenhausstrasse 12, Erlangen 91054, Germany. oliver.bleiziffer@uk-erlangen.de.
authors.forename: Oliver
authors.initials: O
authors.lastname: Bleiziffer
mesh_terms: D000818:Animals; D001854:Bone Marrow Cells / Q000166:cytology* / Q000378:metabolism; D051929:CD146 Antigen / Q000378:metabolism; D019070:Cell Lineage; D002478:Cells, Cultured; D003094:Collagen / Q000737:chemistry; D004338:Drug Combinations; D042783:Endothelial Cells / Q000166:cytology / Q000378:metabolism; D015718:Fibrin Tissue Adhesive / Q000737:chemistry; D007797:Laminin / Q000737:chemistry; D008077:Lipoproteins, LDL / Q000378:metabolism; D008297:Male; D018919:Neovascularization, Physiologic; D019408:Platelet Endothelial Cell Adhesion Molecule-1 / Q000378:metabolism; D011509:Proteoglycans / Q000737:chemistry; D051381:Rats; D011917:Rats, Inbred Lew; D023822:Tissue Engineering; D015854:Up-Regulation; D040301:Vascular Endothelial Growth Factor Receptor-2 / Q000378:metabolism
chemical_list: D051929:CD146 Antigen; D004338:Drug Combinations; D015718:Fibrin Tissue Adhesive; D007797:Laminin; D008077:Lipoproteins, LDL; D019408:Platelet Endothelial Cell Adhesion Molecule-1; D011509:Proteoglycans; C032629:acetyl-LDL; C059485:matrigel; D003094:Collagen; D040301:Vascular Endothelial Growth Factor Receptor-2