title: Recovery of CD45(-)/Lin(-)/SSEA-4(+) very small embryonic-like stem cells by cord blood bank standard operating procedures.
abstract: OBJECTIVE
  Very small embryonic-like (VSEL) stem cells are a rare cell population present in bone marrow, cord blood and other tissues that displays a distinct small cell size and the ability to give rise to cells of the three germ layers. VSEL stem cells were reported to be discarded in the red blood cell fraction by Ficoll-Paque density gradient centrifugation during the processing of bone marrow and cord blood specimens. However, most cord blood banks do not include density gradient centrifugation in their procedures while red blood cells are removed by Hespan sedimentation following the Cord Blood Transplantation Study cord blood bank standard operating procedures (COBLT SOP). To clarify the retention of VSEL stem cells, we investigated the recovery of VSEL stem cells following COBLT SOP guidelines.
  
  
  METHODS
  The recovery of CD45(-)/Lin(-)/SSEA-4(+) VSEL stem cells of umbilical cord blood was examined by flow cytometry before and after COBLT SOP processing, and relative expression of pluripotent genes was analyzed by quantitative polymerase chain reaction.
  
  
  RESULTS
  CD45(-)/Lin(-)/SSEA-4(+) VSEL stem cells were mostly recovered in the final products following COBLT SOP guidelines. The expression of pluripotent genes could be maintained at >80% in products after hetastarch (Hespan; B. Braun Medical Inc., Irvine, CA, USA) processing.
  
  
  CONCLUSIONS
  The rare sub-population of CD45(-)/Lin(-)/SSEA-4(+) VSEL stem cells survived after Hespan sedimentation. This finding suggests that umbilical cord blood units cryopreserved by COBLT SOP in cord blood banks should retain most VSEL stem cells present in the un-processed specimens.
authors.affiliation: Bioresource Collection and Research Center, Food Industry Research and Development Institute, Hsinchu, Taiwan.
authors.forename: Yu-Jen
authors.initials: YJ
authors.lastname: Chang
authors.affiliation: Bioresource Collection and Research Center, Food Industry Research and Development Institute, Hsinchu, Taiwan.
authors.forename: Kuei-Erh
authors.initials: KE
authors.lastname: Tien
authors.affiliation: Bioresource Collection and Research Center, Food Industry Research and Development Institute, Hsinchu, Taiwan.
authors.forename: Cheng-Hao
authors.initials: CH
authors.lastname: Wen
authors.affiliation: Bioresource Collection and Research Center, Food Industry Research and Development Institute, Hsinchu, Taiwan.
authors.forename: Tzu-Bou
authors.initials: TB
authors.lastname: Hsieh
authors.affiliation: Bioresource Collection and Research Center, Food Industry Research and Development Institute, Hsinchu, Taiwan. Electronic address: hsm@firdi.org.tw.
authors.forename: Shiaw-Min
authors.initials: SM
authors.lastname: Hwang
mesh_terms: D000328:Adult; D001771:Blood Banks; D015925:Cryopreservation; D053595:Embryonic Stem Cells / Q000166:cytology* / Q000378:metabolism; D005312:Fetal Blood / Q000166:cytology* / Q000378:metabolism; D005434:Flow Cytometry; D006801:Humans; D017493:Leukocyte Common Antigens / Q000378:metabolism*; D012015:Reference Standards; D055746:Stage-Specific Embryonic Antigens / Q000378:metabolism*
chemical_list: D055746:Stage-Specific Embryonic Antigens; C066584:stage-specific embryonic antigen-4; D017493:Leukocyte Common Antigens
keywords: Hespan sedimentation; cell recovery; cord blood bank standard operating procedures; very small embryonic stem cells