Fred Hutchinson researchers have found that they can increase significantly the number of stem cells derived from umbili- cal-cord blood by exposing the blood to a particular molecule, a finding that could have important implications for stem-cell research.
Dr. Irwin Bernstein, a pediatric oncologist in the Clinical Research Division, led a study to see how best to use stem cells from umbilical-cord blood.
To do so, researchers exposed cord blood in the lab to a protein molecule called Delta-1. Although it remains unclear exactly how the molecule works, it increased the number of immature stem cells in a sample of cord blood 100-fold. It also increased the hematopoeitic stem cells, which can evolve into any type of blood cell.
As reported in the Oct. 22 edition of Journal of Clinical Investigation, the researchers next tested their newly harvested cells in mice with deficient immune systems. The immune systems resembled those of leukemia patients who have undergone radiation therapy prior to a bone-marrow transplant. Such patients are left with collapsed immune systems, making them vulnerable to infection.
Results showed the enhanced stem cells were more potent in the mice compared with non-cultured stem cells or stem cells not exposed to Delta-1. This finding is critical, the researchers said, because it helps scientists overcome a major obstacle in the transplantation of cells into adults.
When cells are transplanted, the body typically recognizes them as foreign and tries to reject them.
"What we're interested in, and what we're trying to understand, is what makes a stem cell renew," Bernstein said.
Scientists study stem cells because they can be developed into mature cells involving the immune system, blood or different types of tissue.
The ability to regenerate tissues could have major effects on the treatment of Alzheimer's, Parkinson's and cancer. So far, however, such efforts have been difficult, Bernstein said, because stem cells behave differently in the body - their natural environment - than in the laboratory.
The finding that certain stem cells behave differently when exposed to Delta-1 could improve the ability to control stem development, he said.
"We can use this information to begin to engineer stem cells so we can grow these stem cells in vitro and use them for therapeutic value," Bernstein said. "It used to be thought stem cell differentiation was all random, but it isn't."
[Portions of this story are printed with the permission of United Press International.]