by Steven Ertelt
July 4, 2006
Toronto, Canada (LifeNews.com) — A Japanese researcher presented the results of new studies he conducted showing the ability to turn mouse skin cells into cells that closely resemble embryonic stem cells. The discovery could provide another method for stem cell research that can be effective but doesn’t require the destruction of human life for stem cells.
Shinya Yamanaka of Kyoto University in Japan reported he was able to boost the activity of just four genes to turn the skin cells into embryonic ones. He presented his results at a meeting of the International Society for Stem Cell Research.
Yamanaka said his research team thought they could reprogram adult stem cells to have embryonic properties. His team identified 24 genes that were specifically expressed in mouse embryonic cells and used viral vectors to introduce extra copies of the genes into skin cells taken from mouse tails, according to ScienceNOW Daily News.
When the team inserted copies of the 24 genes into the adult cells, they found a small percentage of the cells took on the embryonic characteristics.
Through a process of elimination, the team found that four genes were most responsible for producing the embryonic-like results. Three of the genes have been studied before, according to ScienceNOW, but a fourth was not typically recognized as producing embryonic-like traits.
When examined further, the embryonic-like adult stem cells formed several kinds of tissue in a petrii dish and produced tumors when injected into the mice — both things that embryonic stem cells do.
Yamanaka’s team has not tried the experiments with human cells yet because of differences in mouse and human development. He said there may be a different set of genes in human cells that would prompt adult cells to act like embryonic ones.
Kevin Eggan of Harvard University, who also works on cell reprogramming, told ScienceNOW her was impressed with Yamanaka’s presentation, but said that more research needs to be done because just 1 in 1,000 adult cells were reprogrammed successfully.
"But this is the litmus test" for finding the genes that are essential for reprogramming, he said.
This isn’t the first time researchers have been able to turn adult stem cells into embryonic ones.
Researchers at Tufts University said in February 2005 that they believe they have discovered an adult stem cell that has the same potential as embryonic stem cells.
The scientists used specialized cell-sorting machines to obtain different types of adult stem cells from the bone marrow of three donors. Tests on the cells show that they appear to be capable of changing into the many varied types of cells that make up the human body.
The bone marrow cells were injected into the hearts of rats who had experienced heart attacks.
Once inserted, some of the cells became new heart muscle and tissue, as adult stem cells have done before in numerous successful experiments. However, the cells also turned into new blood vessels to support the ailing hearts.
Douglas Losordo, the Tufts cardiologist who headed up the research team, said at the time, "I think embryonic stem cells are going to fade in the rearview mirror of adult stem cells."