Optimizing oxygen conditions enhances stem cell recovery

Two very recent papers, published in Cell and Regenerative Medicine, have described research into the advantages of reducing the oxygen exposure stem cells experience during isolation and cultivation, and the cellular mechanisms involved in translating hypoxia into increased stem cell survival and enhanced transplantation efficacy. The data presented by Mantel et al. on hematopoietic stem cells, and by Kay et al. on mesenchymal stem cells, caused quite a stir at the recent ISSCR meeting in Stockholm, as attendees discussed the implications for their own work.

Alasdair Kay and co-workers at Keele University evaluated the impact of various oxygen, glucose and serum levels on culturing human bone marrow-derived MSC’s. They found that the application of more physiological conditions, e.g. 2% oxygen instead of 21% O2 ambient, resulted in significantly increased cell yields; the highest yields were achieved in the stringently controlled hypoxic environment of a workstation. The authors attribute this to deoxygenation/reoxygenation cycles and very brief air exposure for cells cultured in an incubator, as compared to the controlled atmosphere in the workstation. Transcriptome analysis of hMSC’s cultured at 2% (incubator vs workstation) and 21% oxygen revealed scores of genes that were up or downregulated with very little overlap among the subsets. Kay et al. have identified downregulation of bone morphogenetic protein BMP2 expression, modulation of chemokine (C-X-C motif) receptor CXCR2 signaling, and LEPR upregulation as causative factors for enhanced hMSC isolation at hypoxia.

The term extraphysiologic oxygen shock/stress EPHOSS for hematopoietic stem cells experiencing “hyperoxia” outside of their natural niches is introduced by Mantel et al. from Indiana University. They delineated the detrimental effects of even brief exposure of bone marrow and cord blood to ambient conditions as compared to harvesting and processing HSC’s at constant 3% hypoxia. Up to 5-fold increased cell numbers and improved engraftment of transplanted HSC’s as a result of hypoxic conditions led the authors to question the relevance of the work currently being carried out at ambient oxygen. They attribute the beneficial effects of low oxygen on the yield and function of BM and CB stem cells to reduced production of reactive oxygen species ROS, implicating the mitochondrial permeability transition pore MPTP, cyclophilin CypD, and p53 in protection from EPHOSS. Mantel et al. predict that hypoxic processing will be significant for many other cell types and phenomena such as metabolism of cancer cells and stem cell aging.

This article was written by Burga Kalz Fuller, Product Manager at HypOxygen.

 

Alun Kitsell, Burga Kalz Fuller and Daniel Secker
Alun Kitsell, Burga Kalz Fuller and Daniel Secker with a Whitley HI35 Hypoxystation

 

  1. Kay et al. “BMP2 repression and optimized culture conditions promote human bone marrow-derived mesenchymal stem cell isolation” 2015 Med. 10(2), 109-125
  2. Mantel et al. “Enhancing hematopoietic stem cell transplantation efficacy by mitigating oxygen shock” 2015 Cell 161, 1553-1565

 

Hypoxia and stem cells

Later this month, the international stem cell research community will be travelling to Stockholm for the upcoming International Society for Stem Cell Research (ISSCR) meeting covering diverse topics from reprogramming and pluripotency of stem cells through tissue engineering and organ regeneration to therapy with stem cells.

Whitley H135 Hypoxystation
Whitley H135 Hypoxystation

Hypoxia is a crucial parameter determining the fate and development of stem cells, which leads Don Whitley Scientific to exhibit the Hypoxystation controlled environment workstation for low oxygen cell culture (see us on stand no. B15:33). Dr. Burga Kalz Fuller, Product Manager at our American distributor, HypOxygen, has summarized five recent papers delineating the role of hypoxia in stem cell research:

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H135: Taller, Deeper, Wider.

Don Whitley Scientific is proud to present the new Whitley H135 Hypoxystation; the tallest, deepest, widest workstation in our range.

This new hypoxic chamber has a usable internal volume of almost 600 litres and can accommodate a variety of items of equipment such as live cell imaging devices, microscopes, plate readers, etc. (Be sure to discuss your requirements with us at the earliest opportunity). The generous internal height also facilitates easy pipetting. All cell manipulations can be performed without removing them from your required hypoxic conditions.

With a volume twice that of a H35 Hypoxystation, the H135 also comes fitted with a large removable front, available with either two or three ports, plus the same great features and benefits as other Whitley Workstations, including:

  • Rapid 12 litre airlock

    H135 Hypoxystation
    H135 Hypoxystation
  • Three gas operation
  • The Whitley Internal HEPA Filtration System with Enhanced Biological Containment
  • The option of being connected to a Whitley i2 Instrument Workstation
  • 7” full colour touch screen that is Ethernet-enabled for remote access.

Internal dimensions (w x d x h) are 1100mm/43.3” x 750mm/29.5” x 710mm/28”.

External dimensions (w x d x h) are 1452mm/57.25″ x 1056mm/41.5″ x 993mm/39″.

Representatives from Don Whitley Scientific will be attending the Keystone Symposia in Dublin, 12-17 May, where you can be one of the first to see this revolutionary product.

Watch the introductory video here.

 

 

Cell Press Webinar: Hypoxic Microenvironments

The hypoxic microenvironment triggers many of the events underlying cancer progression and stem cell maintenance and/or differentiation. In maintaining oxygen homeostasis, oxygen levels are sensed by mitochondria, communicated by reactive oxygen species (ROS), and conveyed by hypoxia-inducible factors HIF’s. Hypoxia signalling pathways have far-reaching consequences for cellular and tissue processes from metabolism through angiogenesis to metastasis.

Dr. Hannele Ruohola-Baker (University of Washington) and Dr. Randall Johnson (University of Cambridge) will be speaking at the upcoming Cell Press webinar on “Hypoxic Microenvironments”, which Don Whitley Scientific and HypOxygen are proud to sponsor. Dr. Ruohola-Baker’s lab investigates metabolic determinants of and miRNA function in stem cells, and Dr. Johnson examines the effects of hypoxia in cancer and inflammation.
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Free T-Shirt: Hypoxia Research

 

Do you culture cells in hypoxic conditions? For a limited time only, you can earn a free t-shirt by taking a few minutes to answer our questions and help us to better fulfil your cell culture needs.

We want to know what your research focus is, how you conduct your cell culture and how you think oxygen content might influence aspects of your cell culture.

Please click here to complete a very short online form.

Hypoxia and Cancer Metabolism

An ever-increasing number of scientific papers are being produced that highlight the effects and importance of hypoxia in various research fields. Dr Burga Kalz Fuller, Product Manager at our American distributor, HypOxygen, has summarised five interesting and recent papers concerning hypoxia and its role in cancer metabolism research:

“Hypoxia signaling pathways in cancer metabolism: the importance of co-selecting interconnected physiological pathways” Masson & Ratcliffe, 2014.

In this paper, the role of hypoxia – as mediated by HIF, interfacing with many different oncogenic pathways – is reviewed. Activated HIF both suppresses mitochondrial metabolism and up-regulates biosynthesis of intermediates needed by proliferating cells in cancer. Complex relationships between HIF activation and cancer phenotype are discussed in detail by these Oxford UK researchers.

 

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Cell Memory of Hypoxia in Metastases

This paper, entitled “Cellular memory of hypoxia elicits neuroblastoma metastasis and enables invasion by non-aggressive neighbouring cells”, was recently published in Oncology, and investigates the link between the level and duration of cells’ exposure to hypoxia and their ability to form metastases.

The researchers acknowledge that oxygen tension is not homogeneous throughout a tumour (as there will be areas of higher and lower oxygen tension within it) and thus seek to investigate the metastatic potential of cells that have been cultured hypoxically in vitro in comparison to those that have not, when implanted into a chick-embryo model.

Their results showed that cells with hypoxic preconditioning formed metastases in vivo, but cells without hypoxic preconditioning did not. These results support the discovery that the cells which were exposed to hypoxic preconditioning have a “memory” of this previous environment when introduced to normoxic conditions.

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The Science Behind “Three-person Babies”

Last week, the House of Commons voted to allow in vitro fertilisation (IVF) to be carried out with eggs from two different women and sperm from one man, a technique which has been dubbed the “three-person baby”. The vote opened a novel avenue for treating mitochondrial diseases because the actual nuclear mother, whose family would have a history of mitochondrial (MT) diseases, does not pass on her mitochondria, with the baby receiving the female donor’s healthy mitochondria instead.

Dr Burga Kalz Fuller, product manager at HypOxygen, presents an interesting outline of the scientific implications and explains why the media’s term “three-person baby” is a misnomer:

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