title: Engraftment of human cord blood-derived stem cells in preimmune ovine fetuses after ultrasound-guided in utero transplantation.
abstract: OBJECTIVE
  The fetal sheep in utero transplantation model has developed into an important tool to study the efficacy of human in utero stem cell transplantation and gene therapy because of similarities in both the scale and development of immunocompetence relative to gestational age. The aim of this study was to determine whether human stem cells can be successfully transplanted to the first-trimester ovine fetus by use of a newly developed minimally invasive technique.
  
  
  METHODS
  Human cord blood-derived, CD34(+)-enriched stem cells were injected into the peritoneal cavity of 45- to 60-day-old ovine fetuses by using ultrasound-guided transabdominal percutaneous needle puncture. Engraftment was determined 1 to 3 months after birth by flow cytometry with use of human-specific anti-CD45 antibodies.
  
  
  RESULTS
  In contrast to previous studies that used surgical techniques, we observed a fetal loss rate of 24%, significantly below previous values and only marginally higher than natural loss. Successful human cell engraftment was achieved in 18% of lambs available for analysis. Engraftment levels of human cells in bone marrow of the recipient were up to 0.8% of total nucleated cells.
  
  
  CONCLUSIONS
  Ultrasound-guided percutaneous transplantation of stem cells to fetal sheep in the first trimester is feasible. Although we were unable to observe a significant improvement in the level of engraftment of human cells in sheep, the decreased fetal loss rate associated with this technique allows greater use for further studies that use this model of in utero transplantation.
authors.affiliation: Basel Institute for Immunology, Switzerland.
authors.forename: Alan J
authors.initials: AJ
authors.lastname: Young
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Holzgreve
authors.forename: Lisbeth
authors.initials: L
authors.lastname: Dudler
authors.forename: Andreina
authors.initials: A
authors.lastname: Schoeberlein
authors.forename: Daniel V
authors.initials: DV
authors.lastname: Surbek
mesh_terms: D000818:Animals; D018952:Antigens, CD34 / Q000032:analysis; D001854:Bone Marrow Cells / Q000276:immunology; D036101:Cord Blood Stem Cell Transplantation / Q000009:adverse effects / Q000379:methods*; D005260:Female; D005313:Fetal Death / Q000453:epidemiology / Q000209:etiology; D005333:Fetus / Q000601:surgery*; D005434:Flow Cytometry; D005865:Gestational Age; D006801:Humans; D017493:Leukocyte Common Antigens / Q000032:analysis; D011247:Pregnancy; D012756:Sheep; D014183:Transplantation, Heterologous; D014463:Ultrasonography
chemical_list: D018952:Antigens, CD34; D017493:Leukocyte Common Antigens