WASHINGTON – Researchers reported yesterday that they have 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. Such work is legal with private funds but off-limits to federally funded scientists.
The researchers did not transfer the embryos to female monkeys' wombs to grow into full-blown clones. They destroyed them to retrieve the embryonic stem cells growing inside.
Those cells can morph into every kind of cell and tissue in the body, and the team, from the Oregon National Primate Research Center in Beaverton, has coaxed theirs to become monkey nerves and heart cells.
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 team. “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.
Rep. Dave Weldon, R-Fla., who has repeatedly filed legislation to ban human-embryo cloning, warned that the research “would take us down the treacherous path where women are exploited for their eggs.”
