title: Proangiogenic immature myeloid cells populate the human placenta and their presence correlates with placental and birthweight.
abstract: OBJECTIVE
  To determine whether proangiogenic immature myeloid cells are present in human placentas.
  
  
  METHODS
  Biopsies were obtained from 61 placentas of term pregnancies. Percentage of CD45(+)CD33(+)LIN2(-)HLADR(-) immature myeloid cells of total CD45(+) hematopoietic cells was determined by flow cytometry. Location of immature myeloid cells in the placenta was identified using confocal microscopy. The proangiogenic potential of immature myeloid cells was analyzed by endothelial tube formation.
  
  
  RESULTS
  Immature myeloid cells comprise ∼25% of human placental CD45(+) hematopoietic cells and infiltrate placentas in proximity of blood vessels. The percentage of immature myeloid cells correlated positively with placental weight (r(2) = 0.108, P = .01) and birthweight (r(2) = 0.087, P = .02). Endothelial tube formation was increased in the presence of immature myeloid cells as compared with the presence of CD45(+)LIN2(+) control cells.
  
  
  CONCLUSIONS
  Human placentas are populated by immature myeloid cells in the proximity of blood vessels. Consistent with their involvement in angiogenesis, immature myeloid cells accelerated endothelial tube formation. The presence of immature myeloid cells in pathologic pregnancies warrants further studies.
authors: Laboratory for Reproductive Immunology, Hillel Yaffe Medical Center, Faculty of Medicine, Technion - Israel Institute of Technology, Hadera, Israel.
authors: Elad
authors: E
authors: Mei-Dan
authors: Ofer
authors: O
authors: Fainaru
authors: Shay
authors: S
authors: Hantisteanu
authors: Tal
authors: T
authors: Shavit
authors: Adrian
authors: A
authors: Ellenbogen
authors: Mordechai
authors: M
authors: Hallak
mesh_terms: D000328:Adult; D015703:Antigens, CD / Q000378:metabolism; D015214:Antigens, Differentiation, Myelomonocytic / Q000378:metabolism; D001724:Birth Weight; D004730:Endothelium, Vascular / Q000196:embryology; D005260:Female; D005434:Flow Cytometry; D006801:Humans; D007231:Infant, Newborn; D017493:Leukocyte Common Antigens / Q000378:metabolism; D018613:Microscopy, Confocal; D022423:Myeloid Cells / Q000378:metabolism / Q000502:physiology*; D018919:Neovascularization, Physiologic; D009929:Organ Size; D010920:Placenta / Q000033:anatomy & histology* / Q000166:cytology*; D011247:Pregnancy; D063268:Sialic Acid Binding Ig-like Lectin 3
chemical_list: D015703:Antigens, CD; D015214:Antigens, Differentiation, Myelomonocytic; C571163:CD33 protein, human; D063268:Sialic Acid Binding Ig-like Lectin 3; D017493:Leukocyte Common Antigens