title: Endothelial differentiation of adipose-derived stem cells: effects of endothelial cell growth supplement and shear force.
abstract: BACKGROUND
  Adipose tissue is a readily available source of multipotent adult stem cells for use in tissue engineering/regenerative medicine. Various growth factors have been used to stimulate acquisition of endothelial characteristics by adipose-derived stem cells (ASC). Herein we study the effects of endothelial cell growth supplement (ECGS) and physiological shear force on the differentiation of ASC into endothelial cells.
  
  
  METHODS
  Human ASC (CD13(+)29(+)90(+)31(-)45(-)) were isolated from periumbilical fat, cultured in ECGS media (for up to 3 wk), and exposed to physiological shear force (12 dynes for up to 8 d) in vitro. Endothelial phenotype was defined by cord formation on Matrigel, acetylated-low density lipoprotein (acLDL) uptake, and expression of nitric oxide synthase (eNOS), von Willebrand factor (vWF), and CD31 (platelet endothelial cell adhesion molecule, PECAM). Additionally, cell thrombogenicity was evaluated by seeding canine autologous ASC onto vascular grafts implanted within the canine arterial circulation for 2 wk.
  
  
  RESULTS
  We found that undifferentiated ASC did not display any of the noted endothelial characteristics. After culture in ECGS, ASC formed cords in Matrigel but failed to take up acLDL or express the molecular markers. Subsequent exposure to shear resulted in stem cell realignment, acLDL uptake, and expression of CD31; eNOS and vWF expression was still not observed. Grafts seeded with cells grown in ECGS (+/- shear) remained patent (six of seven) at 2 wk but had a thin coat of fibrin along the luminal surfaces.
  
  
  CONCLUSIONS
  This study suggests that (1) ECGS and shear promote the expression of several endothelial characteristics in human adipose-derived stem cells, but not eNOS or vWF; (2) their combined effects appear synergistic; and (3) stem cells differentiated in ECGS appear mildly thrombogenic in vitro, possibly related, in part, to insufficient eNOS expression. Thus, while the acquisition of several endothelial characteristics by adult stem cells derived from adipose tissue suggests these cells are a viable source of autologous cells for cardiovascular regeneration, further stimulation/modifications are necessary prior to using them as a true endothelial cell replacement.
authors.affiliation: Department of Surgery, Thomas Jefferson University, Philadelphia, Pennsylvania, USA.
authors.forename: Lauren J
authors.initials: LJ
authors.lastname: Fischer
authors.forename: Stephen
authors.initials: S
authors.lastname: McIlhenny
authors.forename: Thomas
authors.initials: T
authors.lastname: Tulenko
authors.forename: Negar
authors.initials: N
authors.lastname: Golesorkhi
authors.forename: Ping
authors.initials: P
authors.lastname: Zhang
authors.forename: Robert
authors.initials: R
authors.lastname: Larson
authors.forename: Joseph
authors.initials: J
authors.lastname: Lombardi
authors.forename: Irving
authors.initials: I
authors.lastname: Shapiro
authors.forename: Paul J
authors.initials: PJ
authors.lastname: DiMuzio
mesh_terms: D000273:Adipose Tissue / Q000166:cytology*; D053687:Adult Stem Cells / Q000187:drug effects* / Q000378:metabolism / Q000637:transplantation; D000818:Animals; D002454:Cell Differentiation / Q000187:drug effects*; D002478:Cells, Cultured; D003470:Culture Media; D004285:Dogs; D042783:Endothelial Cells / Q000166:cytology* / Q000378:metabolism; D005260:Female; D006801:Humans; D008077:Lipoproteins, LDL / Q000378:metabolism; D010641:Phenotype; D019408:Platelet Endothelial Cell Adhesion Molecule-1 / Q000378:metabolism; D033081:Shear Strength; D033581:Stem Cell Transplantation / Q000009:adverse effects; D013314:Stress, Mechanical; D013927:Thrombosis / Q000209:etiology
chemical_list: D003470:Culture Media; D008077:Lipoproteins, LDL; D019408:Platelet Endothelial Cell Adhesion Molecule-1; C032629:acetyl-LDL