A new method of producing red blood cells outside the body on a large scale has been developed by researchers at the University of Bristol.
'We have demonstrated a feasible way to sustainably manufacture red cells for clinical use… We've grown litres of it,' said Dr Jan Frayne, one of the authors of the research which was published in Nature Communications.
Previously the most effective technique involved taking stem cells from bone marrow, which makes blood cells in the body, and inducing them to do the same in lab conditions. This was of limited practical success because each stem cell will only make about 50,000 blood cells before dying – by comparison, a few drops of blood can contain around one billion red cells.
Working with NHS Blood and Transplant, the Bristol team overcame this limitation by engineering the stem cells to make them 'immortal', using DNA. from the human papilloma virus (HPV) which causes cervical cancer. Red blood cells cannot continue to divide in the bloodstream, and as they mature they shed their nuclei – and with it the virus DNA. Thus the adult cells that might in the future be given to patients, if the technique is applied in clinical trials, would not contain the any of the HPV genetic material.
'It's a brilliant approach, and they seemed to have solved several of the really important bottlenecks,' said Dr Robert Lanza, chief scientific officer at the Astellas Institute for Regenerative Medicine, who was not involved in the project.
The lab-grown blood is likely to be much more expensive than donated blood, but there may be a number of potential applications. Lab-grown blood could be used for patients with rare blood types for whom a match is difficult to find. It could also be useful in military or disaster situations where there is no time for blood typing people who are critically injured. Interest has also been expressed by researchers of malaria and other blood-borne diseases.
The first studies to assess the safety of manufactured blood are due to begin at the end of this year, although the first trial will not test this new type of blood cell. Even if safety is established, for the time being there is not currently enough capacity to produce it and industrialising the process could be costly.
'To make big huge vats of it would be outside of our ability in a research lab,' said Dr Frayne. 'We'd have to have company interest.'