They officially announced their discovery in the Thursday, November 22, 2007 online edition of the journal Science, and in the December 21, 2007 print edition of the journal.

The report states that the UW team has successfully reprogrammed human skin cells genetically so as to create cells identical to embryonic stem cells. They added four human genes to a virus and then used the altered virus to carry the four genes into the DNA (deoxyribonucleic acid) of fetal fibroblast cells. So far, the UW group has developed eight new stem cell lines in which they converted skin cells into a “pluripotent” state, something that is indistinguishable from embryonic stem cells.

According to UW News article “UW-Madison scientists guide human skin cells to embryonic state”: The finding is not only a critical scientific accomplishment, but potentially remakes the tumultuous political and ethical landscape of stem cell biology as human embryos may no longer be needed to obtain the blank slate stem cells capable of becoming any of the 220 types of cells in the human body. Perfected, the new technique would bring stem cells within easy reach of many more scientists as they could be easily made in labs of moderate sophistication, and without the ethical and legal constraints that now hamper their use by scientists."

Japanese stem cell researcher Shinya Yamanaka, of Kyoto University, led the second group. The Kyoto team’s result (titled “Induction of Pluripotent Stem Cells from Adult Human Fibroblasts by Defined Factors”) was published Monday, November 19, 2007, in the online edition of the journal Cell. The Japanese scientists (which also included Kazutoshi Takahashi, Koji Tanabe, Mari Ohnuki, Megumi Narita, Tomoko Ichisaka, Kiichiro Tomoda) report that they have successfully reprogrammed skin cells of adult mice to function like pluripotent embryonic stem cells.

In their method, they insert four genes into human skin cells in a process called “induced pluripotent cells” (iPS), which reprograms the skin cells to act similar, but not identical to, stem cells. They also showed in their experiment that their induced pluripotent stem cells could become, specifically, brain and heart-muscle cells. They are confident they can perform the same technique on human skin cells.

Both teams of scientists caution that much more work is needed before confirmation can be made that they are on the right road to providing viable stem cells. Yamanaka, also a senior investigator at the Gladstone Institute of Cardiovascular Disease, states, "Further studies are required to determine whether iPS cells can replace human embryonic stem cells," [CNN.com/health]

With the possibility of averting further controversy about working with human embryos, which has plagued stem cell research in the past, dramatic increase in such research is likely to happen in the upcoming months and years.

GICD director Deepak Srivastava said that this new discovery by Yamanaka is “monumental in its importance to the field of stem cell science and its potential impact on our ability to accelerate the benefits of this technology to the bedside. Not only does this discovery enable more research, it offers a new pathway to apply the benefits of stem cells to human disease.” [EurekaAlert]

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