Scientists at McMaster University have discovered how to transform human skin into blood. The researchers had previously used chemicals to transform mouse skin cells into neurons, but this is the first time human cells have been altered in this manner.
The team created blood progenitor cells, the mother cells that multiply to produce other blood cells as well as mature blood cells. Both types of cells are useful in medical treatments, said study leader Mick Bhatia, a stem cell scientist at McMaster University in Hamilton, Ontario.
Bhatia’s team had been focused on generating blood cells for more than 10 years. Stem cells weren’t efficient at generating blood cells that were suitable for clinical use so for the past two years, the team has been converting skin cells directly into blood cells.
By using a trial-and-error approach, the scientists determined which genes needed to be activated to reprogram the cells into blood cells. Then they looked for the right combination of growth factors (or blood proteins that promote development of the new cells) that were needed to move the process along.
They found that they needed to turn on a single gene called OCT4 in the skin cells and that the cells needed to bathe in precisely calibrated combinations of four to six growth factors to make a variety of blood cell types. The approach worked with skin cells taken from adults and from the discarded foreskins of newborns.
Efficient enough to produce usable amounts of blood for transfusions, this technique offers a safer, simpler way of creating transplant tissues without the time-consuming step of making embryonic stem cells. This should provide a desperately needed new source of blood for not only surgical and cancer patients, but also for patients suffering from blood disorders such as anemia. Bhatia says a patch of skin as small as 12 square centimeters (a size routinely removed during grafting operations) would generate sufficient blood for transfusions. “We’ll now go on to work on developing other types of human cell types from skin, as we already have encouraging evidence,”
The ultimate test would be transplanting the cells into humans, says Bhatia, but that isn’t on the cards — at least not yet. “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.” Clinical trials could begin as early as 2012.
The study also raises the prospect that other types of cells could be created from skin cells. Scientists may be able to create brain cells from the skin to help treat patients with Alzheimer’s or Parkinson’s, for example. The researchers also said it would be possible for people with rare blood types to grow their own blood, and freeze it either for their personal use or to help others in the same blood group.