title: Characterization of endothelial colony-forming cells from peripheral blood samples of adult horses.
abstract: OBJECTIVE
  To isolate and characterize endothelial colony-forming cells (ECFCs; a subtype of endothelial progenitor cells) from peripheral blood samples of horses.
  
  
  METHODS
  Jugular venous blood samples from 24 adult horses.
  
  
  METHODS
  Blood samples were cultured in endothelial cell growth medium. Isolated ECFCs were characterized by use of functional assays of fluorescence-labeled acetylated low-density lipoprotein (DiI-Ac-LDL) uptake and vascular tubule formation in vitro. Expression of endothelial (CD34, CD105, vascular endothelial growth factor receptor 2, and von Willebrand factor) and hematopoietic (CD14) cell markers was assessed through indirect immunofluorescence assay and flow cytometry. The number of passages before senescence was determined through serial evaluation of DiI-Ac-LDL uptake, vascular tubule formation, and cell doubling rates.
  
  
  RESULTS
  Samples from 3 horses produced colonies at 12 ± 2.5 days with characteristic endothelial single layer cobblestone morphology and substantial outgrowth on expansion. Equine ECFCs formed vascular tubules in vitro and had uptake of DiI-Ac-LDL (74.9 ± 14.7% positive cells). Tubule formation and DiI-Ac-LDL uptake diminished by passage 5. Equine ECFCs tested positive for von Willebrand factor, vascular endothelial growth factor receptor 2, CD34, and CD105 with an immunofluorescence assay and for CD14 and CD105 via flow cytometry.
  
  
  CONCLUSIONS
  ECFCs can be isolated from peripheral blood of horses and have characteristics similar to those described for other species. These cells may have potential therapeutic use in equine diseases associated with ischemia or delayed vascularization.
authors: Department of Clinical Sciences, College of Veterinary Medicine, Auburn University, Auburn, AL 36849.
authors: Margaret M
authors: MM
authors: Salter
authors: Wen J
authors: WJ
authors: Seeto
authors: Blake B
authors: BB
authors: DeWitt
authors: Sarah A
authors: SA
authors: Hashimi
authors: Dean D
authors: DD
authors: Schwartz
authors: Elizabeth A
authors: EA
authors: Lipke
authors: Anne A
authors: AA
authors: Wooldridge
mesh_terms: D000818:Animals; D018929:Cell Culture Techniques / Q000662:veterinary*; D002454:Cell Differentiation; D042783:Endothelial Cells / Q000166:cytology* / Q000378:metabolism; D005434:Flow Cytometry / Q000662:veterinary; D005455:Fluorescent Antibody Technique / Q000662:veterinary; D006736:Horses; D042461:Vascular Endothelial Growth Factor A / Q000378:metabolism; D014841:von Willebrand Factor / Q000378:metabolism
chemical_list: D042461:Vascular Endothelial Growth Factor A; D014841:von Willebrand Factor