Study Probes Difference Between Embryonic, Adult Stem Cells
Each develops in unique ways, researchers say
WEDNESDAY, Oct. 10, 2007 (HealthDay News) -- Adult stem cells lack a protein called Oct4, which helps maintain embryonic stem cells in an undifferentiated state, U.S. researchers report.
The findings suggest that the ability of stem cells to change into any kind of cell is regulated differently in adult and embryonic stem cells, the researchers said. The study also challenges findings from more than 50 studies that concluded that Oct4 was present in adult stem cells.
Using three independent detection methods to analyze six types of tissue in which Oct4-positive adult stem cells have been reported, the authors of the new study concluded that Oct4 was not present, or was present at only statistically insignificant levels, in these tissues.
The researchers at the Whitehead Institute for Biomedical Research in Cambridge, Mass., also found that Oct4 is not required to maintain mouse adult stem cells in their undifferentiated state and that adult tissues functioned normally when the Oct4 gene was deleted.
The study was published online Oct. 10 in the journal Cell Stem Cells.
Earlier studies may have misapplied analytical techniques or worked with cell cultures that had spent too much time in an incubator, said author Christopher Lengner, a postdoctoral fellow at the Whitehead Institute.
He and his team are now studying the mechanisms used by adult stem cells to change into any kind of cell.
"Is there a common pathway that governs stemness in adult stem cells, or does each stem cell have its own pathway? We don't know yet," Lengner said in a prepared statement.
The U.S. National Institutes of Health has more about stem cells.