Scientists report they've used a cloning technique to reprogramme an ordinary human skin cell to become an embryonic stem cell. In turn, the new stem cell has the potential to transform into any type of cell in the body.
Besides marking a breakthrough in stem cell technology, which has the potential to one day cure a myriad of illnesses, the achievement has some concerned that scientists are moving a step closer to human cloning.
That's because the new stem cell is genetically identical to cells from the person from whom it was derived. Stem cells can differentiate into cells for all of the tissue types that the body needs, such as nerves, muscle and bone.
Cloned monkey the next step?
While Dolly the Sheep was cloned in 1996, and other species have been cloned since, researchers have been unable to clone a primate such as a monkey, chimpanzee or human. However, the technological advances described in the new study are such that "it's a matter of time before they produce a cloned monkey," Jose Cibelli, a cloning expert at Michigan State University who wasn't involved in the study, told the Wall Street Journal.
The new research was published in the journal Cell, and was led by Shoukhrat Mitalipov, a senior scientist at the Oregon National Primate Research Center, in partnership with researchers at Oregon Health & Science University (OHSU).
The research involved a version of what's known as somatic cell nuclear transfer, where the cell's nucleus - which contains all a person's genetic information-- is transferred into an egg cell that has had all of its DNA removed. Once the new nucleus is in place, the unfertilised egg cell proceeds to develop and produce stem cells, according to an OHSU news release.
"Stem cells derived through this technique demonstrated their ability to convert just like normal embryonic stem cells, into several different cell types, including nerve cells, liver cells and heart cells," Mitalipov said in the news release. "While there is much work to be done in developing safe and effective stem cell treatments, we believe this is a significant step forward in developing the cells that could be used in regenerative medicine."
Regenerative medicine is the term used to describe therapies where stem cells are used to regenerate tissues lost to illness or injury.
One key point in the new research: Creation of the new, functioning embryonic stem cell did not involve the use of fertilised embryos, the focus of heated debate over the past decade.
Research may lead to human cloning
Mitalipov's team says the road to success was not easy, because human egg cells seem to be more fragile than those from other species. That meant that methods had to be tested in monkeys first, in a trial-and-error fashion, before moving to human eggs.
The researchers downplayed the notion that this research might somehow lead to human cloning.
"While the method might be considered a technique for cloning stem cells, commonly called therapeutic cloning, the same method would not likely be successful in producing human clones otherwise known as reproductive cloning," OHSU said in a university press release. Attempts over many years to create monkey clones have failed, the university noted, and human cells are even more fragile and less amenable to cloning.
"Our research is directed toward generating stem cells for use in future treatments to combat disease," Mitalipov added. "While nuclear transfer breakthroughs often lead to a public discussion about the ethics of human cloning, this is not our focus, nor do we believe our findings might be used by others to advance the possibility of human reproductive cloning."
Speaking to the Wall Street Journal, Cibelli said he believes the new achievement might encourage someone to attempt human cloning, "though that remains a distant and disturbing prospect."
There's more on the promise of stem cell therapy at the U.S. National Institutes of Health.