WASHINGTON – Researchers in Oregon on Wednesday reported they had created the world’s first fully formed, cloned monkey embryos and harvested batches of stem cells from them – a feat that, if replicated in people, could allow production of replacement tissues or organs with no risk of rejection.
Successful creation of the cloned embryos, each from a single monkey skin cell, effectively settles a long-standing scientific debate about whether primates – the family that includes monkeys and people – are biologically incapable of being cloned, as some had come to believe after years of failures.
That fact alone could reinvigorate a stalled congressional battle over whether restrictions on human embryo cloning should be tightened or loosened. Currently such work is legal with private funds but off-limits to federally funded scientists.
The Oregon researchers did not transfer the embryos to female monkeys’ wombs to grow into full-blown clones, as has been done with several other species. They destroyed them to retrieve the embryonic stem cells growing inside.
Because they were grown from cloned embryos, those cells are genetically matched to the monkey that donated the initial skin cells. That means that any tissues or organs grown from them could be transplanted into that monkey without the need for immune-suppressing drugs.
“We only work with monkeys,” said Shoukhrat Mitalipov, who led the research at the Oregon National Primate Research Center in Beaverton. “But we hope the technology we developed will be useful for other laboratories working on human subjects.”
Practical and ethical hurdles to growing personalized tissues for people are still great – because the still-inefficient technique requires large numbers of women’s eggs, whose retrieval poses medical risks, and because the process would involve creating and destroying human embryos, which many social conservatives reject.
Even short of such applications, experts said, the work could prove medically invaluable by yielding monkey cells and organs with human diseases, which scientists could study and test therapies on.
“This technology potentially allows researchers to look at the early stages of many human diseases,” said Sean Tipton, president of the Coalition for the Advancement of Medical Research, a Washington-based group that advocates for embryonic stem-cell research.
The new work, to be published in an upcoming issue of the journal Nature but released early to quell a wave of Internet-fed rumors, echoes the fraudulent 2004 claims of South Korean researchers that they had isolated stem cells from cloned human embryos, an episode that gave a black eye to the “therapeutic cloning” field.