The researchers used a molecular technique called single nucleotide polymorphism (SNP) analysis to study stem cell lines, and specifically to compare the number of copy number variations in both early and intermediate-stage human iPS cells with their respective parental, originating cells.
Drs. Nagy and Otonkoski and their teams found that iPS cells had more genetic abnormalities than their originating cells and embryonic stem cells. Interestingly, however, the simple process of growing the freshly generated iPS cells for a few weeks selected against the highly mutant cell lines, and thus most of the genetic abnormalities were eventually 'weeded out.'
"However, some of the mutations are beneficial for the cells and they may survive during continued growth," said Dr. Otonkoski, Director and Senior Scientist at the Biomedicum Stem Cell Center.
Stem cells have been widely touted as a source of great hope for use in regenerative medicine, as well as in the development of new drugs to prevent and treat illnesses including Parkinson's disease, spinal cord injury and macular degeneration. But techniques for generating these uniquely malleable cells have also opened a Pandora's Box of concerns and ethical quandaries. Health Canada, the U.S. Food and Drug Administration and the European Union consider stem cells to be drugs under federal legislation, and as such, subject to the same regulations.
"Our results suggest that whole genome analysis should be included as part of quality control of iPS cell lines to ensure that these cells are genetically normal after the reprogramming process, and then use them for disease studies and/or clinical applications," said Dr. Nagy.
"Rapid development of the technologie
|Contact: Karin Fleming|
Samuel Lunenfeld Research Institute