Blastomere Blowup
A NOVEL WAY TO HARVEST STEM CELLS INTRIGUES AND INFLAMES BY CHARLES 0. CHOI

A method that can generate human em­bryonic stem cells without harming embryos? In August biotechnology firm Advanced Cell Technology (ACT) in Worcester, Mass., claimed it had developed just such a procedure. The company touted it as a way around the firestorm of controversy surrounding the conventional technique for growing these cells, which de­stroys human embryos. Most researchers find the method in­triguing, because it might lead to new and maybe better stem cell lines. But several also argue that it raises fresh dilemmas.
Scientists investigate hu­man embryonic stem cells be­cause they can become any other kind of cell. As such, they hold great promise in regener­ating body parts. Convention­ally, researchers rely on embry­os produced during in vitro fertilization (IVF) attempts, removing the inner cell mass from embryos that have grown to 50 to 100 cells. Current­ly at least 400,000 frozen embryos lie un­used in U.S. fertility clinics, and thousands are typically discarded annually.
ACT's vice president of research and sci­entific development, Robert Lanza, and his colleagues experimented with 16 unused hu­man embryos from an earlier, eight- to 10-cell stage. Physicians routinely pluck single cells from IVF embryos at that stage for pre-implantation genetic diagnosis (PCD), which scans these cells, known as blastomeres, for diseases. Embryos can compensate for the loss and have so far developed into some 1,500 apparently healthy children since this procedure was introduced more than a decade ago.
Starting with a technique similar to PGD, the ACT researchers used micro eyedroppers to extract 35 blastomeres one or two at a time from the six highest-grade embryos they had. They then generated two stable human embryon­ic stem cell lineages, which they report­ed online August 23 via Nature, These cell lines apparently behave like their conventional counterparts, capable of replicating for months on end and de­veloping into other cell types.
ACT ended up destroying its em­bryos—to make the most of the few embryos it had, Lanza's team eviscer­ated them by taking several cells from each (up to seven). But because stan­dard PGD does not kill the embryo, the scientists declared that their method in principle can deliver stem cell lines without killing the embryos.
Researchers regard the cells gener­ated by this method as scientifically in­triguing, because they come from ear­lier-stage embryos. Development neurobiologist Arnold Kriegstein of the University of California, San Francisco, noted that the 50- to 100-cell-stage embryo cell lines cannot split to be­come twins, whereas eight- to 10-cell-stage embryos such as those ACT used can. It suggests that the younger cells "might have better potential for turning into certain kinds of tissue than cur­rently used lines," he says. "Only fur­ther experiments will tell."
Even if investigators can get the method to work, however, the contro­versy will not abate. It remains uncer­tain whether single human blastomeres could develop into living beings. If they can, this technique would land the cell lines back in the original controversy. "In sheep and rabbits, for example, sin­gle cells are capable of developing into viable animals; however, the same does not appear to be true for mice," said James Battey, chair of the National Institutes of Health stem cell task force, at a Senate hearing in September.
In addition, the ACT study has already destroyed 16 embryos. Hence, whether the method can add to the number of federally funded human embryonic stem cell lines is unclear, the U.S. President's Council on Bioethics reported, because the law prevents funding of any additional lines produced through the destruction of embryos. Lanza says that ACT probably would file for federal funding to continue the work. The company has announced that—with the WiCell Research Institute in Madison, Wis., which hosts the National Stem Cell Bank—it would distribute ACT's new cell lines to U.S. scientists, provided that the federal government will fund research using them.
In the end, even if ACT overcomes the technical and ethical issues, it may face one last obstacle: resistance from physicians and expectant parents. In the Nature paper, the extracted cells were not grown in isolation but incubated near one another to help them thrive from chemical signals they each release. {A single blastomere isolated from other cells is less likely to lead to a cell line.)
Lanza says that ACT has some evidence that lone blastomeres placed next to the embryos from which they were extracted could grow without risk to the embryos. Bur whether such assurance would be good enough for IVF doctors and their patients is not clear, points out IVF gynecologist Outi Hovatta of the Karolinska Institute in Swe­den. They may not want to take any chances with their future children even if ACT ultimately becomes ready, willing and able.

In this article, Charles Q. Choi describes the latest procedure that the firm Advanced Cell Technology (ACT) has developed for harvesting embryonic stem cells capable of not harming the embryos. In short, they remove single stem cells from embryos in the eight- to ten-cell stage. Although ACT killed their embryos by removing too many cells, they say that embryos can compensate for the loss of one or two cells because approximately 1500 children have lived after having a similar procedure done before in vitro fertilization (IVF).One advantage of the new stem cell lines is that come from an earlier cell stage capable of splitting into twins, unlike our current lines. They also has the potential to save the lives of the embryos. However, there is still the largest ethical question: if stem cells can become any type of cell, what’s to stop them from fully developing into children? If they can, then killing them in research is the same as killing an embryo.
I think that further experiments into the possible ability of these early stem cell lines to become children need to be conducted. If they can, then research on them should be stopped and the money used to research adult stem cells, which are currently yielding more information than their embryonic counterparts. However, if they aren’t capable of ‘life’ (tremendously vague term because they are living cells, but not necessarily living humans) the possible benefits are vast and enticing.