Elizabeth Cohen: Major stem cell report published

CNN Medical Correspondent Elizabeth Cohen

Scientists at the University of Wisconsin medical school announced that they have for the first time turned human embryonic stem cells into blood cells. CNN Medical Correspondent Elizabeth Cohen discusses this latest development.

Q: What's the significance of the announcement?

COHEN: This is what everyone's been waiting for. This is the first published report that researchers have managed to make human embryonic stem cells into something. Embryonic stem cells by themselves are useless -- the trick is to turn them into one of the 220 types of cells or tissues that make up the human body. The University of Wisconsin researchers appear to have done just that by turning the stem cells into blood cells identical to those produced by the human body.

MORE STORIES Scientists make blood from stem cells     EXTRA INFORMATION Read more about the stem cell research in Proceedings of the National Academy of Sciences     RESOURCES Message Boards: Human embryo research

Q: How'd they make these blood cells?

COHEN: Here's a somewhat simplified explanation. Researchers took an embryo from a fertility clinic and scooped out the stem cells from inside it. After allowing these human embryonic stem cells to multiply, the scientists grew some of the stem cells in a culture with blood, human bone marrow cells, and vitamins. The cells that grew into all sorts of blood cells, including red cells, white cells, and platelets.

Q: So when can we expect to see these blood cells help sick people?

COHEN: Not for quite a while. Dr. Dan Kaufman, the lead author of the University of Wisconsin paper said in five to ten years "optimistically" we could see some actual therapeutic uses for these cells. If scientists can overcome several hurdles, these cells could possibly be used to treat all sorts of blood disorders, including leukemia, lymphoma, and anemia. Dr. Kaufman said these lab-made blood cells are "a potential way of alleviating the sort of chronic shortage that we're always in for blood cells and blood products."

Q: What hurdles do they need to overcome?

COHEN: They know that these lab-made blood cells look just like regular blood cells, but they're not sure exactly how they'll behave once put into a real person -- for example, there could be immune response problems. Also, they'd need to be able to mass produce these blood cells in a financially feasible way to make them useful in the real world.