DURHAM, N.C. -- Medical researchers have been searching for a reliable method to separate rare and primitive stem cells from human blood because these cells can regenerate a blood supply and immune system damaged by disease or medical treatment.
Now researchers from the Duke Comprehensive Cancer Center at Duke University Medical Center have developed a new method to identify and isolate stem cells from samples of umbilical cord blood based on an enzyme in the cells. The enzyme, which is more abundant in stem cells than other blood cells, changes a fluorescent tag the researchers developed to a form that can't escape the cell.
The brightest cells -- the stem cells -- are then selected automatically.
Current separation methods, primarily focused on detecting proteins on the surface of stem cells, are complex and expensive and are complicated by the possibility that not all stem cells express these proteins, the researchers say. The advance, reported in the Aug. 3 issue of the Proceedings of the National Academy of Sciences (PNAS), has immediate implications for laboratory research involving stem cells. There is also the potential for clinical applications if further experiments show that the selected stem cells can mature into needed blood cells in humans, says the study's principal investigator, Dr. Clay Smith, an associate professor of hematology and oncology.
In the shorter run, the technique could help researchers isolate enough of the elusive cells to investigate many fundamental questions regarding stem cells -- from how they maintain their primitive nature, to how they differentiate into specific kinds of cells, to even what tissues might contain them.
To date, several types of stem cell have been identified. Embryonic stem cells,
found in developing fetuses, can mature into any of the body's cell types.
Hematopoietic stem cells, those isolated by Smith and his colleagues, are found
in bone marrow and blood, including umbilical cor
Contact: Joanna Downer
Duke University Medical Center