In a major research breakthrough, scientists have found a way to transform human skin cells into blood.

While researchers had produced blood out of skin cells of a mouse, this is for the first time scientists have cracked the issue for humans. When the fibroblast cells of a mouse are treated with the correct chemicals, it can be transformed into neurons2 and heart muscle3.

"It takes us a step along the line to believing that you can produce anything from almost anything," says Ian Wilmut, an embryologist and director of the MRC Centre for Regenerative Medicine in Edinburgh, UK. Such 'direct conversions' also offer a potentially safer, simpler tool for creating patient-specific cell therapies than is promised by adult cells reprogrammed to become stem cells (known as induced pluripotent stem cells, or iPS cells).

As the red blood cells created from stem cells didn’t result in the adult form of hemoglobin, researchers undertook this project. "Those cells, because they think they're embryonic, make embryonic and fetal blood," he says.
Researchers collected skin fibroblasts from participants, infected the cells with a virus that inserted the gene OCT4. Later they grew them up in a soup of immune-stimulating proteins called cytokines.

It is one of the Yamanaka factors used to transform fibroblasts into iPS cells, but Bhatia noted that there was no proof that the blood progenitor cells passed an embryonic state.

The progenitors did, however, produce all three classes of blood cells — white blood cells, red blood cells and platelets — all of which seemed to function as they should, according to a battery of experiments. The red blood cells made adult hemoglobin, not the fetal form.

In future, Bhatia might try to transplant these cells into humans. "The clinical side is going to be a lot of work," he says. "At least from our estimation, this is the most encouraging result we've seen for using blood cells for cell-replacement therapy."

Deepak Srivastava, a developmental biologist and director of the Gladstone Institute of Cardiovascular Disease in San Francisco, California, says direct conversion could be simpler, but cautioned that these converted cells could have drawbacks.

"It is still too early to tell whether they will be as good as the real thing once they are inside patients,” says George Daley, a stem-cell biologist at Children's Hospital Boston in Massachusetts.