Is Tiny the Mouse a Big Leap for Stem Cells?

July 23, 2009 — -- When stem cells exploded into the public vocabulary a decade ago, they were already politically complicated. They were hailed as having the potential to cure myriad diseases. But the creation of embryonic stem cells involved the destruction of an embryo and many people, including President George W. Bush, objected on moral grounds.

Now, a Chinese team has reported in the journal Nature that it developed a work-around -- mouse stem cells from "somatic" tissues, meaning they come from the body (actually, in this case, fibroblasts, or cells that make up the body's connective tissues) and, thus, don't raise the ethical issues.

What's more, the researchers say they were able to make the new stem cells -- in the complex jargon of the field -- "pluripotent," which means they were able to morph into any other kind of cell in the body as they reproduced. That meant they were as useful as stem cells removed from embryos. The new cells were described as "iPS" cells, short for induced Plutipotent Stem cells.

The researchers say they used the cells to create 27 new, healthy mouse pups. They named the first Tiny -- "Xiao Xiao" in Chinese.

"We are confident that tremendous good can come from demonstrating the versatility of reprogrammed cells in mice," Fanyi Zeng, associate director of the Shanghai Institute of Medical Genetics, wrote in an e-mail to The Associated Press. Zeng was one of the co-authors of the study.

Dr. Curt Freed, a stem cell researcher at the University of Colorado School of Medicine, said the new research is "a very important confirmation that the iPS cells are essentially identical in character to embryonic stem cells.

"We are now entering an era in which almost any cell in the body can be converted to almost any other cell by inserting a few reprogramming genes," he told ABC News. But he warned that the technique used by the Chinese team was complex and not very efficient: only about two percent of the cloning attempts they made resulted in healthy baby mice.

Dr. George Daley, who does research at Children's Hospital and the Dana-Farber Cancer Institute in Boston, was also cautious.

"This very exciting paper proves that some iPS cells can perform like embryonic stem cells in making a whole mouse from cells in a Petri dish. This does not prove that all iPS cells can do this."