Novel cryoprotectant significantly improves the post-thaw recovery and quality of HSC from CB

Cytotherapy. 2006;8(1):57-61. doi: 10.1080/14653240500501021.


Background: Hematopoietic stem cells (HSC) have traditionally been frozen using the cryoprotectant DMSO in dextran-40, saline or albumin. However, the process of freezing and thawing results in loss of HSC numbers and/or function.

Methods: This study investigated the use of CryoStor for the freezing of HSC from cord blood (CB). CB donations (n = 30) were collected under an Institutional Ethics Committee-approved protocol, volume reduced and frozen using three different methods of cryoprotection. Aliquots were frozen with either 10% DMSO in dextran-40, 10% DMSO in CryoStor or 5% DMSO in CryoStor. Prior to freezing samples were separated for nucleated cell (NC) and CD34+ counts and assessment of CD34+ viability. Aliquots were frozen and kept in vapor phase nitrogen for a minimum of 72 h. Vials were rapidly thawed at 37 degrees C and tested for NC and CD34+ counts and CD34+ viability and colony-forming unit (CFU) assay.

Results: Cells frozen with CryoStor in 10% DMSO had significantly improved NC (P < 0.001), CD34+ recovery, viable CD34+ (P < 0.001) and CFU numbers (P < 0.001) compared with dextran in 10% DMSO. CryoStor in 5% DMSO resulted in significantly improved NC (P < 0.001) and CFU (P < 0.001).

Discussion: These results suggest that improved HSC recovery, viability and functionality can be obtained using CryoStor with 10% DMSO and that similar if not better numbers can be obtained with 5% DMSO compared with dextran-40 with 10% DMSO.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Antigens, CD34 / metabolism
  • Cell Nucleus / metabolism
  • Cell Survival / drug effects
  • Colony-Forming Units Assay
  • Cryopreservation / methods*
  • Cryoprotective Agents / pharmacology*
  • Fetal Blood / cytology*
  • Freezing
  • Hematopoietic Stem Cells / cytology*
  • Hematopoietic Stem Cells / drug effects*
  • Humans


  • Antigens, CD34
  • Cryoprotective Agents