您现在的位置: 纽约时报中英文网 >> 华尔街日报中英文版 >> 医疗 >> 正文


更新时间:2014-4-18 21:40:15 来源:华尔街日报中文网 作者:佚名

Scientists Make First Embryo Clones From Adults

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 in part 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.


这项成果周四发表在科学期刊《干细胞》(Cell Stem Cell)上,意味着实验室培育人体组织的研究又向前迈进了一步。制造出的人体组织可以用来治疗心脏病、阿兹海默症等多种疾病。两名捐献者均为男性,年龄是35岁和75岁。


研究报告的撰写人之一、马萨诸塞州马尔堡Advanced Cell Technology Inc.首席科学长兰扎(Robert Lanza)说,年龄越大的人体细胞克隆后可治疗的疾病就越多,如果不能用成人细胞培育组织,这项技术的实用价值就有限。这项研究的经费一部分来自韩国政府,是在加利福尼亚州一个研究所完成的。



和去年由俄勒冈健康科学大学(Oregon Health and Science University)完成的胚胎实验一样,兰扎和他的同事首先从一枚未受精的人类卵细胞中摘除原有DNA,然后植入从一名捐献者的成熟细胞中提取出的DNA。合成后的新细胞自动按照植入DNA序列“重新编程”,直到胚胎进入囊胚期,即由50至100个细胞组成的一个中空的球形幼胚。


俄勒冈健康科学大学发育生物学家米塔利波夫(Shoukhrat Mitalipov)说,“我很高兴有人验证了我们的实验并且证明了它的真实性。”米塔利波夫主持了2013年的研究项目,兰扎和他的同事又在今年把它重现了一遍。



遗传学与社会中心(Center for Genetics and Society)是设在加州伯克利的一个非营利性公益组织,该组织执行理事Marcy Darnovsky说,如果放任疯子科学家或不孕不育症医生利用公开的技术培育克隆人,无疑会加大风险,所以应当出台一部合适的联邦法律。