Artificial blood from stem cells

Blood donations may become a thing of the past due to advances in stem cell technology, newspapers report. The Daily Telegraph says that a new way has been discovered of growing  “potentially unlimited supplies of blood in the lab”. Researchers in the USA have found that human embryonic stem cells – cells that can mature into a variety of cells in the body – can be turned into oxygen-carrying red blood cells.

This is laboratory research and it is still at an early stage. Although the findings show great potential, further work will be needed to explore the applications, drawbacks and safety issues of the technique before it could reach a stage where it would be possible to transplant these manufactured blood cells into a live recipient. For the foreseeable future, there will be no change to the current system of reliance upon blood donation, and hospital blood banks remain in great need of donated blood to meet constant demands.

Where did the story come from?

Shi-Jiang Lu and colleagues from Advanced Cell Technology, University of Illinois at Chicago, and the Mayo Clinic, US, carried out this research. No sources of funding are reported for this research. It was published in the peer-reviewed medical journal: Blood .

What kind of scientific study was this?

This was a laboratory study designed to demonstrate that it is possible for human embryonic stem cells to be formed and matured into oxygen-carrying red blood cells (erythrocytes) and produced on a large scale.

The researchers used four different stem cell lines (reported by code names in the journal paper) and a complex three-week laboratory procedure involving four stages to generate and mature red blood cells. The stages involved forming the red blood cell line from the undifferentiated stem cells, forming and expanding blast cells from which the red cells would develop, differentiating the blast cells into red cells and then “enriching” the red cells.

The resulting red blood cells were washed in an antibody mixture and stained so that the researchers could examine the cell structure. Another laboratory method was used to assess the capacity for the cells to carry oxygen. The red blood cells were also assessed for their characteristic “blood type”, by looking for A or B and rhesus antigen markers on the cell surface (“O” type blood – rhesus negative cells without A, B or rhesus antigens – are ideal, as these can be transfused into people with any blood type).

What were the results of the study?

The researchers found that, on examination, the cells produced still expressed foetal and embryonic structures; however, after maturation they also expressed a particular structure (a beta-globin chain) which is a feature of red blood cells in adults. After culture in the lab, expression of this chain increased from 0% to over 16%.

The cells also underwent structural and nucleic changes which made them more like red blood cells, with an abundance of haemoglobin (the molecule that carries oxygen in red blood cells) found in the cytoplasm of the cell. However, the cells were larger than normal, with a greater diameter. The cells were found to have an oxygen-carrying capacity which was similar to normal red blood cells; they also responded to changes in acidity in a similar way. The blood type – determined by A, B and rhesus antigen expression on the cells – differed depending on which stem cell line they had come from.

What interpretations did the researchers draw from these results?

The researchers conclude that it is possible for human embryonic stem cells to be formed and matured into oxygen-carrying red blood cells (erythrocytes) and produced on a large scale. Therefore, there is the potential for developing an “inexhaustible and donorless source of cells for human therapy”.

What does the NHS Knowledge Service make of this study?

This study has provided an initial demonstration of a system by which large numbers of functional oxygen-carrying red blood cells could be developed from human embryonic stem cell lines. However, the research is still at an early stage. Although the findings show great potential, further work will be needed to investigate the applications, drawbacks and safety issues of the technique before it could reach a stage where it were possible to transplant these manufactured blood cells into a live recipient. For the foreseeable future there will be no change to the current system of reliance upon blood donation, and hospital blood banks remain greatly in need of donated blood to meet constant demands.