A group of researchers have successfully cloned primate embryos for the first time and used them to create stem cells, opening up the possibility that the same could be done with humans.
Using a technique called “somatic cell nuclear transfer,” the researchers produced rhesus macaque monkey embryos from adult monkey skin cells and isolated two embryonic stem cell lines from them, according to the paper entitled “Producing primate embryonic stem cells by somatic cell nuclear transfer,” reported Wednesday in an advance online publication of the journal Nature.
Shoukhrat Mitalipov, a professor at Oregon Health and Science University in Portland, led the research team.
Because they can differentiate into virtually any cell in the body, embryonic stem cells are thought to hold the potential to alleviate many degenerative diseases while avoiding rejection by the patient’s immune system. Stem cells derived from a patient’s own body would be genetically identical to the rest of the body, and so would not create an immune response.
Prior to this research, somatic cell nuclear transfer had been successfully used this way only with mice.
South Korean researcher Hwang Woo-Suk claimed in 2004 that he created cloned embryonic stem cells from humans, but it was later discovered that his results were fabricated. Mitalipov et al. actually reported his team’s research at a conference in June, but publication of the results was reportedly delayed until a separate research team could confirm them, so as to avoid the possibility of more false claims.
The process used in this research was much like that used to clone Dolly the sheep, but the embryos were never allowed to develop into full animals. Nevertheless, the news has renewed the debate on the ethics and advisability of cloning and stem cell research.
“It’s scary — this is the sort of Frankenstein science we’re all worried about,” Joe Scheidler, national director with the Pro-Life Action League, told TechNewsWorld. “Science thinks it’s so all-knowing, but it can be very dangerous. If you have nothing guiding you but your own instincts and curiosity, you’re going to end up in a mess.”
Yet the progression towards human cloning is probably inevitable, Scheidler added, simply because it’s possible. “Anything they can do, they will do,” he said. “For what good? I don’t know.”
Others, however, argue that the possible good is considerable.
“This technology is enormously important,” Robert Lanza, chief scientific officer with Advanced Cell Technology, told TechNewsWorld. “Prior to this, people thought primate cloning was impossible, and this shows that’s clearly not the case.”
Research on helping those with serious diseases such as cardiovascular disease or diabetes has historically been limited by a shortage of usable human tissues, as well as the likelihood of rejection of transplanted materials by the patient’s immune system, Lanza noted. Typically, high-powered drugs are required to overcome patients’ immune responses, bringing on a host of additional side-effects, he added.
If a diabetic patient’s own skin cell could be used to clone embryonic stem cells, much the way the researchers did in this study, both of those problems would be eliminated, Lanza explained.
Those genetically identical stem cells could then be turned into insulin-producing cells and transplanted back into the patient, he added.
With just 100 lines of stem cells, “it turns out you can get a complete genetic map for half of the U.S. population,” Lanza added.
Such embryonic stem cells are immortal, so with a bank of them, “it would just be a matter of pulling out stem cells that match the particular patient,” he explained.
The Legal Scenario
“There are those who would seek to ban the use of any techniques that could lead to human reproductive cloning, and this demonstrates the folly of that strategy,” Sean Tipton, president for the Coalition for the Advancement of Medical Research, told TechNewsWorld. “I think this shows the importance of keeping somatic cell nuclear transfer research legal.”
Currently, there is no ban on cloning humans in the United States, though some states have adopted their own laws.
In 2005, UN member nations adopted a non-binding ban on all forms of human cloning, but “it’s more of a suggestion or an advisory — it doesn’t have enough clout,” Arthur Caplan, director of the Center for Bioethics at the University of Pennsylvania, told TechNewsWorld.
“When you get to monkeys and have some success, you will find techniques you’re pretty sure will work in humans because the biology gap is narrow compared with goats or sheep,” he explained. “And that leads to a few key questions.”
First, “should anybody be allowed to try this for reproductive purposes, to create people? I’d say no, because the risks of sick, malformed or stillborn animals in cloning makes experimentation with this technique at present completely unethical,” Caplan said.
Second is the question of whether the techniques should be allowed on human embryos in research contexts. “We definitely need a law, but I think the research should proceed as long as embryos stay in dishes,” Caplan said. “They’re not people, and they may not even be potential people, yet they can be used to save people.”
Perhaps the hardest question, however, will be what happens if key discoveries are made outside the United States.
“The crucial fact about research in cloning is that it’s not whether it will happen, but where,” Caplan pointed out.
Britain, China, Singapore, Israel and other countries are all doing or planning to do such research, he said.
“So from an ethics point of view, opponents of this type of research have to answer the question, if a cure comes out of another country, should we prohibit that cure from entering the U.S.?” he explained. “I’d say there’s no way that will happen.”