A company specialising in embryonic stem cell research has reported in the leading journal Blood that it can create red blood cells from embryonic stem cells. In a company press release Robert Lanza, of Advanced Cell Technology, highlighted the importance of his results.

“Limitations in the supply of blood can have potentially life-threatening consequences for patients with massive blood loss. Embryonic stem cells represent a new source of cells that can be propagated and expanded indefinitely, providing a potentially inexhaustible source of red blood cells for human therapy.”

The news made headlines everywhere, but a bit of scepticism is due, even though Blood is an important, peer-reviewed journal. First, ACT is on the verge of running out of cash and has a history of making sensational claims which get abundant media coverage even though the advances have little practical application.

Second, although ACT's method was 100 times more efficient than previous efforts, most of the cells had embryonic or fetal versions of globin, the compound in red blood cells that carries oxygen. Only a few appeared to contain the adult globin that would be needed by patients, according to Eric Bouhassira, a professor of stem cell biology and regenerative medicine at Albert Einstein College of Medicine in New York.

Finally, the blood would be far too expensive to produce at the moment – perhaps thousands of dollars per unit.