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Bottle Turning Strategy Boosts Erythrocyte Production from Cord Blood

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Review of  “Large-Scale Ex Vivo Generation of Human Red Blood Cells from Cord Blood CD34+ Cells” from STEM CELLS Translational Medicine by Stuart P. Atkinson

The ex vivo production of red blood cells (RBCs), or erythrocytes, from hematopoietic stem and progenitor cells (HSPCs) represents a promising strategy for the production of large amounts of transfusable human blood. However, while previous studies have demonstrated the plausibility of this approach [1], problems related to the scaling-up of current bioreactor technologies have limited the clinical application.

Now, a team from the laboratory of Yongping Jiang (Chinese Academy of Medical Sciences & Peking Union Medical College, China) have described the development of an optimized ex vivo “bottle turning device” culture system to generate massive amounts of human erythrocytes from cord blood (CB) CD34+ progenitor cells [2]. This encouraging new STEM CELLS Translational Medicine study employed mouse and non-human primate models to prove the safety and functionality of CB-derived erythrocytes and, therefore, the enormous potential of their newly developed system.

So how did Zhang et al. achieve such success?

  • The team optimized a four-step 21-day protocol for the ex vivo expansion and differentiation of erythrocytes from human CD34+ CB cells with stage-specific growth media employing a bottle turning device culture system
    • Step 1: Expansion of CD34+ cells
    • Step 2: Differentiation of CD34+ cells into the erythroid lineage 
    • Step 3: Further proliferation and differentiation of erythroid cells
    • Step 4: Maturation into erythrocytes
  • The bottle turning system maintained medium-dissolved oxygen levels and inhibited cell aggregation, while the optimized media cut costs significantly
  • Large scale production generated ~3 × 1011 cells (~50% enucleation rate) from an initial 1 x 106 CD34+ CB cells and 120 liters of medium
    • Therefore, one human CB CD34+ cell could  generate 200 million erythrocytes, meaning the possibility of producing 500 blood transfusion units from one CB cell unit (5 million CD34+ cells)
  • Gene expression analysis revealed an upregulation of fetal-type hemoglobin (Aγ-globin, Gγ-globin) and adult-type hemoglobin (β-globin)
    • Hemoglobin content also rose to levels similar to normal human RBCs
    • Functionally, the study observed oxygen binding and dissociation abilities equivalent to in vivo RBCs 
  • Transplantation of ex vivo erythrocytes into a NOD/SCID murine model demonstrated that cells fully matured in vivo, becoming more enucleated and expressed the human RhD blood group antigen
    • All mice continued to survive with no apparent deleterious side effects 6 months after transplantation
  • Transplantation of ex vivo erythrocytes into an NHP model enhanced the hematological recovery and ameliorated hypoxia in NHPs with hemorrhagic anemia with no adverse effects

The authors note that their strategy achieves higher expansion levels in a shorter period, from a readily available cell source in comparison to similar studies [3-6] and so, could represent a massive step toward the clinic for ex vivo HSPC-derived human erythrocytes.

Stay tuned to the Stem Cells Portal to keep in touch with the new approach.

References

  1. Giarratana MC, Rouard H, Dumont A, et al. Proof of principle for transfusion of in vitro-generated red blood cells. Blood 2011;118:5071-5079.
  2. Zhang Y, Wang C, Wang L, et al. Large-Scale Ex Vivo Generation of Human Red Blood Cells from Cord Blood CD34+ Cells. STEM CELLS Translational Medicine 2017;6:1698-1709.
  3. Timmins NE, Athanasas S, Gunther M, et al. Ultra-high-yield manufacture of red blood cells from hematopoietic stem cells. Tissue Eng Part C Methods 2011;17:1131-1137.
  4. Baek EJ, Kim HS, Kim S, et al. In vitro clinical-grade generation of red blood cells from human umbilical cord blood CD34+ cells. Transfusion 2008;48:2235-2245.
  5. Leberbauer C, Boulme F, Unfried G, et al. Different steroids co-regulate long-term expansion versus terminal differentiation in primary human erythroid progenitors. Blood 2005;105:85-94.
  6. Miharada K, Hiroyama T, Sudo K, et al. Efficient enucleation of erythroblasts differentiated in vitro from hematopoietic stem and progenitor cells. Nat Biotechnol 2006;24:1255-1256.