Combined mild hypoxia and bone marrow mesenchymal stem cells improve expansion and HOXB4 gene expression of human cord blood CD34+ stem cells


  • Fatemeh Mohammadali Department of Hematology and Blood Banking, Faculty of Medical Sciences, Tarbiat Modares University, Tehran
  • Saeid Abroun Department of Hematology and Blood Banking, Faculty of Medical Sciences, Tarbiat Modares University, Tehran
  • Amir Atashi 1. Department of Hematology and Blood Banking, Faculty of Medical Sciences, Tarbiat Modares University, Tehran; 2. Stem Cell and Tissue Engineering Research Center, Shahroud University of Medical Sciences, Shahroud


cord blood, hematopoietic stem cells, CD34 cells, mesenchymal stem cells, hypoxia, HOXB4


Paper description:

  • Expansion modalities of hematopoietic stem cells have been performed with the ultimate goal of improving engraftment of cord blood
  • Expansion in culture remains a challenge because of our limited knowledge of factors that drive self-renewal beside expansion.
  • Combining bone marrow mesenchymal stem cells and mild hypoxia (5% O2 tension) in serum-free culture not only improves expansion but can also significantly enhance self-renewal of hematopoietic stem cells.
  • Our findings contribute to the development of more efficient culture systems for the ex vivo expansion of cord blood hematopoietic stem cells for cellular therapy.

Abstract: Cord blood (CB) is a rich source of hematopoietic stem cells (HSC). It has been used successfully to treat a variety of hematological and non-hematological disorders. Beside the advantages of CB, its main disadvantages are the limited number of stem cells available for transplantation and delayed engraftment. Identifying strategies to enhance expansion and self-renewal of HSCs can improve transplantation efficiency. The aim of this study was to examine different culture conditions on ex vivo expansion and homeobox protein Hox-B4 gene (HOXB4) expression in cord blood CD34+ stem cells. Human cord blood CD34+ HSC were cultured in serum-free medium supplemented with cytokines with and without a feeder layer in normoxia (21% O2) and mild hypoxia (5% O2).At the end of 7 days of culture, the highest number of total nucleated cells (TNC), CD34+ cells, colony forming units (CFUs) and HOXB4  mRNA were observed in a co-culture of  HSC with a bone marrow mesenchymal stem cell(MSC) feeder layer at 5% O2.We concluded that the combination of  bone marrow (BM)-MSC and mild hypoxia (5% O2) not only improved HSC expansion but also enhanced HOXB4 gene expression as a self-renewal marker of HSC, and better mimicked the niche microenvironment conditions.

Received: October 28, 2017; Revised: December 21, 2017; Accepted: January 14, 2018; Published online: January 26, 2018

How to cite this article: Mohammadali F, Abroun S, Atashi A. Combined mild hypoxia and bone marrow mesenchymal stem cells improve expansion and HoxB4 gene expression of human cord blood CD34+ stem cells. Arch Biol Sci. 2018;70(3):…


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How to Cite

Mohammadali F, Abroun S, Atashi A. Combined mild hypoxia and bone marrow mesenchymal stem cells improve expansion and HOXB4 gene expression of human cord blood CD34+ stem cells. Arch Biol Sci [Internet]. 2018Aug.20 [cited 2023Mar.22];70(3):433-41. Available from: