title: Hemangioblasts from human embryonic stem cells generate multilayered blood vessels with functional smooth muscle cells.
abstract: BACKGROUND
  The formation and regeneration of functional vasculatures require both endothelial cells (ECs) and vascular smooth muscle cells (SMCs). Identification and isolation of progenitors with potential for both EC and SMC lineage differentiation from an inexhaustible source, such as human embryonic stem (hES) or induced pluripotent stem cells, will be desirable for cell replacement therapy.
  
  
  METHODS
  Recently, we have developed a serum-free and animal feeder-free differentiation system to generate blast cells (BCs) from hESCs. These cells possess the characteristics of hemangioblasts in vitro and are capable of repairing damaged retinal vasculatures, restoring blood flow in hind-limb ischemia and reducing the mortality rate after myocardial infarction in vivo. We demonstrate here that BCs express markers of SMCs and differentiate into smooth muscle-like cells (SMLCs), in addition to ECs and hematopoietic cells.
  
  
  RESULTS
  When BCs from individual blast colonies were cultured in SMC medium, they differentiated into both ECs and SMLCs, which formed capillary-vascular-like structures after replating on Matrigeltrade mark. The SMLCs expressed SMC-specific markers (alpha-SM actin and calponin) and contracted upon treatment with carbachol. When implanted in nude mice, these cells formed microvasculature with ECs in Matrigel plaques. The BCs differentiated into both ECs and SMLCs, and incorporated into blood vessels after injection into ischemic tissue.
  
  
  CONCLUSIONS
  These results demonstrate that hemangioblasts (BCs) generated from hESCs are tripotential and can provide a potentially inexhaustible source of cells for the treatment of human blood and vascular diseases.
authors.affiliation: Advanced Cell Technology, Worcester, Massachusetts, MA 01605, USA.
authors.forename: Shi-Jiang
authors.initials: SJ
authors.lastname: Lu
authors.forename: Yordanka
authors.initials: Y
authors.lastname: Ivanova
authors.forename: Qiang
authors.initials: Q
authors.lastname: Feng
authors.forename: Chenmei
authors.initials: C
authors.lastname: Luo
authors.forename: Robert
authors.initials: R
authors.lastname: Lanza
mesh_terms: D000818:Animals; D001808:Blood Vessels / Q000166:cytology* / Q000378:metabolism; D002454:Cell Differentiation; D002478:Cells, Cultured; D053595:Embryonic Stem Cells / Q000166:cytology* / Q000378:metabolism; D005260:Female; D055018:Hemangioblasts / Q000166:cytology / Q000378:metabolism*; D006801:Humans; D007150:Immunohistochemistry; D051379:Mice; D008819:Mice, Nude; D032389:Myocytes, Smooth Muscle / Q000166:cytology* / Q000637:transplantation