title: Pericytes from infantile hemangioma display proangiogenic properties and dysregulated angiopoietin-1.
abstract: OBJECTIVE
  Infantile hemangioma (IH) is a rapidly growing vascular tumor affecting newborns. It is composed of immature endothelial cells and pericytes that proliferate into a disorganized mass of blood vessels. We isolated pericytes from IH (Hem-pericytes) to test our hypothesis that Hem-pericytes are unable to stabilize blood vessels.
  
  
  RESULTS
  We injected pericytes in vivo, in combination with endothelial cells, and found that Hem-pericytes formed more microvessels compared with control retinal pericytes. We, thereby, analyzed proangiogenic properties of the Hem-pericytes. They grew fast in vitro, and were unable to stabilize endothelial cell growth and migration, and expressed high levels of vascular endothelial growth factor-A compared with retinal pericytes. Hem-pericytes from proliferating phase IH showed lower contractility in vitro, compared with Hem-pericytes from the involuting phase and retinal pericytes. Consistent with a diminished ability to stabilize endothelium, angiopoietin 1 was reduced in Hem-pericytes compared with retinal pericytes. Normal retinal pericytes in which angiopoietin 1 was silenced produced conditioned medium that stimulated endothelial cell proliferation and migration.
  
  
  CONCLUSIONS
  We report the first successful isolation of patient-derived pericytes from IH tissue. Hem-pericytes exhibited proangiogenic properties and low levels of angiopoietin 1, consistent with a diminished ability to stabilize blood vessels in IH.
authors.affiliation: Vascular Biology Program and Department of Surgery, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA.
authors.forename: Elisa
authors.initials: E
authors.lastname: Boscolo
authors.forename: John B
authors.initials: JB
authors.lastname: Mulliken
authors.forename: Joyce
authors.initials: J
authors.lastname: Bischoff
mesh_terms: D042683:Angiopoietin-1 / Q000235:genetics / Q000378:metabolism*; D000818:Animals; D015415:Biomarkers / Q000378:metabolism; D002450:Cell Communication; D002465:Cell Movement; D049109:Cell Proliferation; D002469:Cell Separation / Q000379:methods; D002478:Cells, Cultured; D017077:Culture Media, Conditioned / Q000378:metabolism; D015536:Down-Regulation; D006391:Hemangioma / Q000378:metabolism* / Q000473:pathology; D061307:Human Umbilical Vein Endothelial Cells / Q000378:metabolism / Q000637:transplantation; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D051379:Mice; D008819:Mice, Nude; D009389:Neovascularization, Pathologic; D020286:Pericytes / Q000378:metabolism* / Q000473:pathology / Q000637:transplantation; D034622:RNA Interference; D012333:RNA, Messenger / Q000378:metabolism; D012171:Retinal Vessels / Q000378:metabolism; D013997:Time Factors; D014162:Transfection; D042461:Vascular Endothelial Growth Factor A / Q000378:metabolism
chemical_list: C467630:ANGPT1 protein, human; D042683:Angiopoietin-1; D015415:Biomarkers; D017077:Culture Media, Conditioned; D012333:RNA, Messenger; C467484:VEGFA protein, human; D042461:Vascular Endothelial Growth Factor A