title: Oct-4-expressing cells in human amniotic fluid: a new source for stem cell research?
abstract: BACKGROUND
  It is the hope of investigators and patients alike that in future the isolation of pluripotent human stem cells will allow the establishment of therapeutic concepts for a wide variety of diseases. A major aim in this respect is the identification of new sources for pluripotent stem cells. Oct-4 is a marker for pluripotent human stem cells so far known to be expressed in embryonal carcinoma cells, embryonic stem cells and embryonic germ cells.
  
  
  METHODS
  Cells from human amniotic fluid samples were analysed for mRNA expression of Oct-4, stem cell factor, vimentin and alkaline phosphatase via RT-PCR. Oct-4 protein expression was investigated by Western blot analysis and immunocytochemistry. Oct-4-positive cells were also analysed for the expression of cyclin A protein via double immunostaining.
  
  
  RESULTS
  Performing RT-PCR, Western blot and immunocytochemical analyses revealed that in human amniotic fluid in the background of Oct-4-negative cells a distinct population of cells can be found, which express Oct-4 in the nucleus. Oct-4-positive amniotic fluid cell samples also express stem cell factor, vimentin and alkaline phosphatase mRNA. The Oct-4-positive amniotic fluid cells are actively dividing, proven by the detection of cyclin A expression.
  
  
  CONCLUSIONS
  The results presented here suggest that human amniotic fluid may represent a new source for the isolation of human Oct-4-positive stem cells without raising the ethical concerns associated with human embryonic research.
authors.affiliation: Obstetrics and Gynecology, University of Vienna, Prenatal Diagnosis and Therapy, Währinger Gürtel 18-20, 1090 Vienna, Austria.
authors.forename: Andrea-Romana
authors.initials: AR
authors.lastname: Prusa
authors.forename: Erika
authors.initials: E
authors.lastname: Marton
authors.forename: Margit
authors.initials: M
authors.lastname: Rosner
authors.forename: Gerhard
authors.initials: G
authors.lastname: Bernaschek
authors.forename: Markus
authors.initials: M
authors.lastname: Hengstschläger
mesh_terms: D000653:Amniotic Fluid / Q000166:cytology*; D015153:Blotting, Western; D002455:Cell Division; D002469:Cell Separation / Q000379:methods*; D019925:Cyclin A / Q000032:analysis; D004268:DNA-Binding Proteins / Q000032:analysis / Q000235:genetics*; D005260:Female; D005333:Fetus; D015870:Gene Expression; D006801:Humans; D050814:Octamer Transcription Factor-3; D039904:Pluripotent Stem Cells / Q000737:chemistry / Q000166:cytology* / Q000502:physiology; D011247:Pregnancy; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014157:Transcription Factors
chemical_list: D019925:Cyclin A; D004268:DNA-Binding Proteins; D050814:Octamer Transcription Factor-3; C494173:POU5F1 protein, human; D014157:Transcription Factors