New York – Two new mouse experiments may show how to obtain human embryonic stem cells without ethical hurdles, a step that could allow federal funding for such research, scientists reported Sunday.
Currently, scientists must sacrifice human embryos to harvest such cells, which can form any tissue type and are seen as valuable for studying and treating illnesses such as diabetes and Parkinson’s disease.
Objections to the embryo destruction have led to a ban on federal funding for such work, which scientists say hampers research.
The new methods, detailed Sunday in the online edition of the journal Nature, seek to obtain the cells without destroying embryos.
The Coalition for the Advancement of Medical Research, which advocates federal funding of stem-cell research, cautioned that despite the goal of avoiding ethical quandaries, the new approaches “will not sit well with many who oppose embryonic stem-cell research.”
In the standard method of harvesting stem cells, researchers wait five days or so after fertilization until the embryo has become a ball of up to 150 cells. They obtain stem cells from the interior of the ball, which destroys the embryo.
One of the new mouse studies borrowed a lab technique used in fertility clinics, called pre-implantation genetic diagnosis, or PGD. It is used to screen embryos for genetic disorders.
In the study, researchers plucked a single cell from eight-cell mouse embryos, which were about 2 days old. While fertility clinics use such a cell for genetic testing, the researchers cultured the plucked cells and found they behaved like embryonic stem cells. The embryos, meanwhile, went on to produce mice.
The result suggests that when clinics do PGD, they could let the cell they remove divide into two, and use one resulting cell for genetic testing and the other to establish a stem-cell line, said Robert Lanza of Advanced Cell Technology in Worcester, Mass., an author of the study.
The second study used a modified form of therapeutic cloning, a technique that aims to generate stem cells that genetically match a patient. As with normal therapeutic cloning, scientists took eggs whose DNA-containing nuclei had been removed and inserted in each one a nucleus from a body cell of a mouse. Before the insertion, they blocked the action of a gene in the nuclei to ensure that the eggs couldn’t produce an embryo that can implant in a uterus.
Yet the eggs divided and grew enough to yield stem cells.
