Skin cells made to mimic stem cells

< Prev | 1 | 2

"I'm very impressed that Jamie was able to identify another set of factors," Yamanaka told msnbc.com. "I really think our combination and his combination are not the only two combinations in the world. There have to be different combinations."

Thomson's research group reported that 198 stem cell-like colonies grew from 900,000 cells in one of the experiments, while Yamanaka said 50,000 cells yielded 10 colonies.

"This efficiency may sound very low, but it means that from one experiment, with a single 10-centimeter dish, you can get multiple iPS [induced pluripotent stem] cell lines," Yamanaka noted in a news release from Cell.

Story continues below ↓

advertisement | your ad here

Perfecting the recipe
If the recipe for stem cell-like behavior can be perfected, individualized pluripotent cells could be created to reflect a particular disease condition — for example, allowing researchers to test potential treatments for Parkinson's disease on living human neurons created in a culture dish.

Eventually, your cells could be converted and grown into tissue suitable for transplantation back into your body, with no fear of immune rejection. In the process, no human embryos would be destroyed, and no human eggs would be used — easing the ethical concerns that have dogged stem cell research in the past.

But that bright future depends on a series of big ifs.

First of all, the function of the reprogrammed cells will have to be compared closely with the function of actual embryonic stem cells. "I'd be surprised if these cells do all the same tricks as stem cells derived from embryos," Lanza told msnbc.com.

Also, in both experiments, the four-gene recipe was added to the skin cells using a virus as the delivery package. "The FDA [Food and Drug Administration] would never allow us to use these virus-modified cells in patients," Lanza said.

Yu acknowledged that the viral delivery method would raise a red flag for medical treatments but said alternative gene-delivery methods may become available in the future. "A lot of groups are working on this model," she said.

Yamanaka's recipe poses an additional quandary because it includes c-Myc, a gene that has been linked to cancerous tumors. However, the newly published research hints that c-Myc may not be strictly necessary for the recipe to work. "We have been working on that very seriously," Yamanaka said. "All I can say is that we have submitted a paper regarding that aspect, and we hope that that paper will be accepted soon."

A back door to cloning?
Yamanaka also said the reprogramming technique could allow for the creation of egg cells as well as sperm cells from the same person, male or female.

"Making sperm from a male who has some kind of infertility problem, that may be very helpful," he said. "But making sperm from a female iPS cell, and eggs from a male — I think both those procedures should be banned, because the only purpose of that is to make clones."

Yamanaka said he felt a grave responsibility to make sure his technology was used properly.

Click for related content

Opinion: 'Panacea' cells revive ancient hopes
Cosmic Log: An interview with James Thomson

"My purpose is to avoid ethical issues, but I am generating new ethical issues," he said. "So I will talk to the Japanese government to avoid the misuse of this kind of technology."

Thomson, however, said he hoped the ethical issues would give way over time to "routine science" — and eventually to routine medical treatments as well. He said that would serve as a satisfying ending to a saga that began nine years ago, when he and his colleagues at the University of Wisconsin were the first researchers to isolate human embryonic stem cells.

"You can work terribly hard in science, but sometimes a lot of dumb luck is involved," he said. "Somehow, fate has smiled on us twice."

< Prev | 1 | 2