"This is not something that's going to be available tomorrow or next year," Kaufman says, but the research does represent a key step forward in the quest to direct stem cells to become a specific cell type.

Writing in PNAS, Kaufman and his colleagues show that stem cells can be directed to become what are known to scientists as hematopoietic precursor cells (or hematopoietic colony-forming cells), cells that display distinct biochemical markers and gene products characteristic of blood and bone marrow cells in the body. Moreover, these precursor cells go on to form colonies of white blood cells, red blood cells and platelets, cells identical to those that arise from human bone marrow.

If perfected, the technology could significantly improve human blood supplies.

"There is generally a shortage of blood," says Kaufman, and if the technology matures it "may one day be possible to augment that blood supply."

The work at Wisconsin was accomplished in tissue culture by exposing undifferentiated stem cells to bone marrow and other cells as well as growth factors in order to encourage them down the developmental pathway to becoming blood.

The need for certain kinds of blood cells for transplant is acute. According to Kaufman, only about 25 percent of patients who need blood or bone marrow transplants from another person to treat leukemias and other cancers get those transplants. "A goal," he says, "would be to better treat those remaining 75 percent" of patients unable to get transplants for lack of well-matched donor cells.

There are about 20,000 bone marrow transplants conducted annually in the United States to treat leukemias and other diseases. In humans and other animals, blood is constantly renewed in bone marrow and marrow transplants have p
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Contact: Terry Devitt
trdevitt@facstaff.wisc.edu
608-262-8282
University of Wisconsin-Madison
3-Sep-2001