Hypoxia enhances proliferation and tissue formation of human mesenchymal stem cells.

Changes in oxygen concentrations affect many of the innate characteristics of stem and progenitor cells. Human mesenchymal stem cells (hMSCs) were maintained under hypoxic atmospheres (2% O(2)) for up to seven in vitro passages. This resulted in approximately 30-fold higher hMSC expansion over 6 weeks without loss of multi-lineage differentiation capabilities. Under hypoxia, hMSCs maintained their growth-rates even after reaching confluence, resulting in the formation of multiple cell layers. Hypoxic hMSCs also displayed differences in the cell and nuclear morphologies as well as enhanced ECM formation and organization. These changes in cellular characteristics were accompanied by higher mRNA levels of Oct-4 and HIF-2alpha, as well as increased expression levels of connexin-43, a protein used in gap junction formation. The results from this study demonstrated that oxygen concentrations affected many aspects of stem-cell physiology, including growth and in vitro development, and may be a critical parameter during expansion and differentiation.

[1]  W. Bickmore,et al.  Distinctive nuclear organisation of centromeres and regions involved in pluripotency in human embryonic stem cells , 2005, Journal of Cell Science.

[2]  P. Schiller,et al.  Marrow-isolated adult multilineage inducible (MIAMI) cells, a unique population of postnatal young and old human cells with extensive expansion and differentiation potential , 2004, Journal of Cell Science.

[3]  T. Jensen,et al.  Adult human mesenchymal stem cell as a target for neoplastic transformation , 2004, Oncogene.

[4]  Bartolozzi,et al.  Incubation of murine bone marrow cells in hypoxia ensures the maintenance of marrow‐repopulating ability together with the expansion of committed progenitors , 2000, British journal of haematology.

[5]  B. Aronow,et al.  Hypoxia induces chondrocyte-specific gene expression in mesenchymal cells in association with transcriptional activation of Sox9. , 2005, Bone.

[6]  R. Zhao,et al.  Proliferation and differentiation of bone marrow stromal cells under hypoxic conditions. , 2006, Biochemical and biophysical research communications.

[7]  D. Kemp,et al.  Human adipose-derived stem cells display myogenic potential and perturbed function in hypoxic conditions. , 2006, Biochemical and biophysical research communications.

[8]  R. Béliveau,et al.  Hypoxia Promotes Murine Bone‐Marrow‐Derived Stromal Cell Migration and Tube Formation , 2003, Stem cells.

[9]  A. Caplan,et al.  Cultivation of rat marrow‐derived mesenchymal stem cells in reduced oxygen tension: Effects on in vitro and in vivo osteochondrogenesis , 2001, Journal of cellular physiology.

[10]  M. Pittenger,et al.  Multilineage potential of adult human mesenchymal stem cells. , 1999, Science.

[11]  Moustapha Kassem,et al.  Induction of Adipocyte‐Like Phenotype in Human Mesenchymal Stem Cells by Hypoxia , 2004, Stem cells.

[12]  M. Longaker,et al.  Effect of reduced oxygen tension on chondrogenesis and osteogenesis in adipose-derived mesenchymal cells. , 2006, American journal of physiology. Cell physiology.

[13]  V. Praloran,et al.  Primitive human HPCs are better maintained and expanded in vitro at 1 percent oxygen than at 20 percent , 2000, Transfusion.

[14]  J. Stains,et al.  Cell-to-cell interactions in bone. , 2005, Biochemical and biophysical research communications.

[15]  W. Grayson,et al.  Human Mesenchymal Stem Cells Tissue Development in 3D PET Matrices , 2004, Biotechnology progress.

[16]  I. Sekiya,et al.  Expansion of Human Adult Stem Cells from Bone Marrow Stroma: Conditions that Maximize the Yields of Early Progenitors and Evaluate Their Quality , 2002, Stem cells.

[17]  J. Trosko,et al.  Ignored Hallmarks of Carcinogenesis: Stem Cells and Cell‐Cell Communication , 2004, Annals of the New York Academy of Sciences.

[18]  C. Green,et al.  Bone morphogenetic protein‐2 modulation of chondrogenic differentiation in vitro involves gap junction‐mediated intercellular communication , 2002, Journal of cellular physiology.

[19]  Feng Zhao,et al.  Effects of hypoxia on human mesenchymal stem cell expansion and plasticity in 3D constructs , 2006, Journal of cellular physiology.

[20]  M. Mattson,et al.  Gap junctional communication is required to maintain mouse cortical neural progenitor cells in a proliferative state. , 2004, Developmental biology.

[21]  F. Guilak,et al.  Influence of oxygen on the proliferation and metabolism of adipose derived adult stem cells , 2005, Journal of cellular physiology.

[22]  M. Csete,et al.  Oxygen in the Cultivation of Stem Cells , 2005, Annals of the New York Academy of Sciences.

[23]  R. Roberts,et al.  Low O2 tensions and the prevention of differentiation of hES cells. , 2005, Proceedings of the National Academy of Sciences of the United States of America.

[24]  Y. Shav-Tal,et al.  Reorganization of nuclear factors during myeloid differentiation , 2001, Journal of cellular biochemistry.

[25]  D. Yew,et al.  Effects of hypoxia on the proliferation and differentiation of NSCs , 2007, Molecular Neurobiology.

[26]  S. Bruder,et al.  Growth kinetics, self‐renewal, and the osteogenic potential of purified human mesenchymal stem cells during extensive subcultivation and following cryopreservation , 1997, Journal of cellular biochemistry.

[27]  A. Pébay,et al.  Presence of Functional Gap Junctions in Human Embryonic Stem Cells , 2004, Stem cells.

[28]  J. Davies,et al.  Adult human bone marrow-derived mesenchymal progenitor cells are capable of adhesion-independent survival and expansion. , 2003, Experimental hematology.