Red blood cells grown in a laboratory are to be tested in patients for the first time by pioneering British scientists.
The first volunteers are expected to be treated by late 2016. If successful, the trial could pave the way to the wide-scale use of artificial blood derived from stem cells.
Blood cells freshly made in the laboratory are likely to have a longer life span than those taken from donors, which typically last no more than 120 days.
They would also be free from infectious agents such as viruses or the rogue prion proteins that cause Creuzfeldt-Jakob Disease (CJD).
Professor Marc Turner, medical director at the Scottish National Blood Transfusion Service (SNBTS), who is leading the £5 million project at the University of Edinburgh, said: "Producing a cellular therapy which is of the scale, quality and safety required for human clinical trials is a very significant challenge. B ut if we can achieve success with this first-in-man clinical study it will be an important step forward to enable populations all over the world to benefit from blood transfusions.
"These developments will also provide information of value to other researchers working on the development of cellular therapies."
The pilot study will involve no more than about three patients, who may be healthy volunteers or individuals suffering from a red blood cell disorder such as thalassaemia.
They will receive a small, five millilitre dose of laboratory-made blood to see how it behaves and survives in their bodies.
The blood cells will be created from ordinary donated skin cells called fibroblasts which are genetically reprogrammed into a stem cell-like state.
The resulting induced pluripotent stem (iPS) cells have the same ability as embryonic stem cells to develop into virtually any kind of body tissue.
Chemicals will be used to coax the iPS cells to mature into red blood cells suitable for injection into a living person.
The aim is to produce relatively rare O rhesus negative blood that can safely be given to 95% of the population, and the skin cell donors will have to belong to this blood group.
A £5 million strategic award from the Wellcome Trust charity is funding the research being carried out by a consortium that includes blood donation services in England, Scotland and Ireland.
Dr Joanne Mountford, from the University of Glasgow, who is head of cell therapy research & development at the SNBTS, said: "This is very much about blood services looking to their future. Our vision is to start replacing donor blood over the next 20 years."
Dr Ted Bianco, director of technology transfer at the Wellcome Trust, said: "Harnessing the power of stem cell biology to contribute to healthcare is one of the most exciting opportunities we can expect to see reach fruition in the coming years. But one should not underestimate the challenge of translating the science into routine procedures for the clinic.
"Nowhere is this more apparent than in the challenge Professor Turner and colleagues have set out to address, which is to replace the human blood donor as the source of supply for life-saving transfusions, knowing that each unit of blood contains no less than a trillion red cells."