"We can get iPS-like colonies, basically, in about 16 days, compared to 28 days to 32 days using [skin]," said Wu, a Stanford stem cell expert. "And if you count the number of colonies in [skin] versus fat ... we get about 20 times more the number of iPS colonies."
The research appears online today in the journal Proceedings of the National Academy of Sciences.
To create the stem cells, the scientists injected Trojan horse-like viruses into smooth muscle cells found in fat that surrounds blood vessels. Once inside, the viruses introduced genes that reprogrammed the cells, spurring them to grow into new forms.
Previously, this process had required growing the stem cells in a culture dish with nutrients from mouse cells. This had raised alarms about the potential for contamination from mouse proteins—a potential obstacle to government approval, Longaker, the plastic surgeon, said.
That the new method works at all is "somewhat surprising" and remains something of a mystery, Longaker said.
Sidestepping Stem Cell Controversy
The fat and skin methods allow researchers to sidestep the ethical controversy over the use of embryonic stem cells from cell lines originally harvested from unused human embryos from in vitro fertilization clinics.
In addition, Longaker noted, tissue or organs grown from a patient's own stem cells should be less likely to be rejected by the body.
The speediness of the fat method, in particular, could be lifesaving, he added.
For example, if a surgeon wanted to implant new heart tissue—derived from a heart attack victim's own fat—into a patient, the doctor might have only a short time before scar tissue would compromise the operation.
If he or she were able to generate the tissue within a few weeks, Longaker said, that "would be a big deal."
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