Blood substitutes can save the lives of people unable to receive transfusions for medical or ethical reasons. 

Although modern blood transfusions are practised universally and are remarkably safe, they are not completely without risk. Rare clinical side effects associated with transfusions, coupled with the costs and complications of processing and administering real blood have all spurred the search for effective substitutes. 

Oxygen therapeutics, often called blood substitutes, are fluids that can be injected to help with oxygen transport around the body. A limited number of blood substitutes have already been approved for clinical use, and further products are being tested, said Kenneth Lowe from the University of Nottingham, UK.

Lowe is a scientific coordinator of the EU-funded multi-centre European project 'Genomics and Blood Substitutes for 21st Century Europe.' One of the project's aims is to use genetically modified plants and microorganisms as 'cell factories' to produce blood substitute components. 

To date, research into substitutes has focused on two main methods: the 'biomimetic approach' - using natural haemoglobin to mimic the body's oxygen transport process - and the 'abiotic approach' - using chemically inert, fluorinated liquids to achieve the same result. 

Now, scientists have produced human haemoglobin using the cell factory approach. Producing large amounts of pure material remains a challenge, said Lowe. But, he explained, the approach could overcome some of the issues, including disease transmission and patient acceptance, that surround human- and animal-derived blood substitutes.

Discussing the future use of these therapeutics, Lowe anticipates that they will contribute to modern blood conserving strategies for the 21st century.' They will also 'increase transfusion options for patients and practitioners,' he said. 

Thomas Chang, whose pioneering work in artificial blood research spans five decades, warned that, if a new infective agent should emerge, 'it would be disastrous if no blood substitutes, even first-generation blood substitutes, were immediately available. It is good to see that increasing efforts are being carried out on basic research and development in this area around the world,' he added.

Kathryn Lees