title: Conditioned Medium from Placental Mesenchymal Stem Cells Reduces Oxidative Stress during the Cryopreservation of Ex Vivo Expanded Umbilical Cord Blood Cells.
abstract: BACKGROUND
  The limited cell dose in umbilical cord blood (UCB) necessitates ex vivo expansion of UCB. Further, the effective cryopreservation of these expanded cells is important in widening their use in the clinics. During cryopreservation, cells experience oxidative stress due to the generation of reactive oxygen species (ROS). Conditioned medium from mesenchymal stem cells (MSCs-CM) has been shown to alleviate the oxidative stress during wound healing, Alzheimer's disease and ischemic disease. This premise prompted us to investigate the influence of MSCs-CM during cryopreservation of expanded UCB cells.
  
  
  RESULTS
  CM-was collected from cord/placental MSCs(C-MSCs-CM, P-MSC-CM). UCB CD34+cells were expanded as suspension cultures in serum free medium containing cytokines for 10 days. Cells were frozen with/without C-MSCs-CM and or P-MSCs-CM in the conventional freezing medium containing 20%FCS +10%DMSO using a programmable freezer and stored in liquid nitrogen. Upon revival, cells frozen with MSCs-CM were found to be superior to cells frozen in conventional medium in terms of viability, CD34+content and clonogenecity. Priming of revived cells for 48 hrs with MSCs-CM further improved their transplantation ability, as compared to those cultured without MSCs-CM. P-MSCs-CM radically reduced the oxidative stress in cryopreserved cells, resulting in better post thaw functionality of CD34+ cells than with C-MSCs-CM. The observed cryoprotective effect of MSCs-CM was primarily due to anti-oxidative and anti-apoptotic properties of the MSCs-CM and not because of the exosomes secreted by them.
  
  
  CONCLUSIONS
  Our data suggest that MSCs-CM can serve as a valuable additive to the freezing or the priming medium for expanded UCB cells, which would increase their clinical applicability.
authors: Stem Cell Laboratory, National Centre for Cell Science, NCCS complex, University of Pune Campus, Ganeshkhind, Pune, 411007, Maharashtra, India.
authors: Darshana
authors: D
authors: Kadekar
authors: Stem Cell Laboratory, National Centre for Cell Science, NCCS complex, University of Pune Campus, Ganeshkhind, Pune, 411007, Maharashtra, India.
authors: Sonal
authors: S
authors: Rangole
authors: Stem Cell Laboratory, National Centre for Cell Science, NCCS complex, University of Pune Campus, Ganeshkhind, Pune, 411007, Maharashtra, India.
authors: Vaijayanti
authors: V
authors: Kale
authors: Stem Cell Laboratory, National Centre for Cell Science, NCCS complex, University of Pune Campus, Ganeshkhind, Pune, 411007, Maharashtra, India.
authors: Lalita
authors: L
authors: Limaye
mesh_terms: D000818:Animals; D018952:Antigens, CD34 / Q000378:metabolism; D002374:Catalase / Q000378:metabolism; D049109:Cell Proliferation / Q000187:drug effects; D002470:Cell Survival / Q000187:drug effects; D002478:Cells, Cultured; D015925:Cryopreservation; D017077:Culture Media, Conditioned / Q000494:pharmacology*; D055354:Exosomes / Q000378:metabolism; D005312:Fetal Blood / Q000166:cytology* / Q000187:drug effects / Q000378:metabolism; D006801:Humans; D006861:Hydrogen Peroxide / Q000633:toxicity; D059630:Mesenchymal Stem Cells / Q000166:cytology / Q000378:metabolism; D051379:Mice; D016688:Mice, Inbred NOD; D016513:Mice, SCID; D018384:Oxidative Stress / Q000187:drug effects*; D017382:Reactive Oxygen Species / Q000378:metabolism
chemical_list: D018952:Antigens, CD34; D017077:Culture Media, Conditioned; D017382:Reactive Oxygen Species; D006861:Hydrogen Peroxide; D002374:Catalase