Scientists Make First Embryo Clones From Adults
Apr 17, 2014 12:13:00 (ET)
By Gautam Naik Scientists for the first time have cloned cells from two adults to create early-stage embryos, and then derived tissue from those embryos that perfectly matched the DNA of the donors.
The experiment represents another advance in the quest to make tissue in the laboratory that could treat a range of maladies, from heart attacks to Alzheimer's. The study, involving a 35-year-old man and one age 75, was published Thursday in the journal Cell Stem Cell.
The creation of the first early-stage human clones, using infant and fetal cells rather than those from adults, was reported last year. The new experiment, with a few tweaks, confirms that striking and controversial breakthrough and also shows the technique works on mature cells.
"The proportion of diseases you can treat with [lab-made tissue] increases with age. So if you can't do this with adult cells, it is of limited value," said Robert Lanza, co-author of the study and chief scientific officer at Advanced Cell Technology Inc. of Marlborough, Mass. The study was funded by the government of Korea and done at a lab in California.
Such experiments are controversial because when cells are extracted from an early-stage human embryo, it destroys the embryo, which some people believe is equivalent to taking a life.
And while the embryos created in these recent experiments may have certain limitations that would prevent them from giving rise to a human clone even if implanted in a womb, that prospect is now scientifically closer.
As with the 2013 experiment, done by researchers at the Oregon Health and Science University, Dr. Lanza and his colleagues first extracted the DNA from an unfertilized human egg and replaced it with the DNA from one of the older donors. The egg automatically "reprogrammed" its DNA until it reached a stage of the embryo known as a blastocyst--a hollow ball of 50 to 100 cells.
Cells from the blastocyst then were cultured in a lab dish and yielded stem cells that were an exact match to the donor's DNA. Those stem cells subsequently were turned into other tissue types, such as heart cells, which potentially could be transplanted into the patient without triggering an immune rejection.
"I'm happy to hear that our experiment was verified and shown to be genuine," said Shoukhrat Mitalipov, a development biologist at Oregon Health and Science University, in Portland, Ore., who led the 2013 study that Dr. Lanza and his colleagues have now replicated.
Despite this advance, experts say it wouldn't be easy to create a full-fledged human clone. Scientists have been trying for years to clone monkeys and have yet to succeed. Even the cloning of less-complicated creatures--from sheep to rabbits and dogs--required years of tweaking, and lots of wasted eggs and deformed fetuses, before it worked.
The recent experiments, nonetheless, have some observers worried. Dozens of countries have laws explicitly banning human reproductive cloning, though there is no equivalent federal law in the U.S. Most U.S. states don't have such laws either, though a few, such as California, do.
"If we're closer to some rogue scientist or fertility doctor using published techniques to create cloned humans, it certainly ups the stakes and means we should be moving to put a federal law in place," said Marcy Darnovsky, executive director of the Center for Genetics and Society, a nonprofit public interest group in Berkeley, Calif. |
